Grod_The_Giant
2016-10-14, 02:11 PM
I... really dislike how 5e uses Ability Scores.
They're weirdly over-prominent, because 5e says "your raw ability is just as important as your training" (Proficiency)
They're painfully structured, because of the widespread use of arrays or point buy, class requirements, and ASIs
They're... oddly disposable, somehow, when you look at it. Plug in your Proficiency Bonus, or Proficiency+1, in place of any ability score, and the game is almost unchanged.
So anyway, this is round three of my attempts to elegantly turn 5e into a purely skill-based game.
The Three Levels of Bonus
On the surface, vanilla 5e characters have two levels of competence-- either they're adding just their Ability Modifier to a roll, or they're adding their Ability Modifier and their Proficiency Bonus. But all Ability Modifiers aren't the same-- you'll usually have one or two you'll focus on, which will begin as +2s and +3s, and others that you care little about, that will spend your entire career circle around the drain of +0. So really there are three, perhaps four categories: Good Ability Modifier plus Proficiency, good Ability Modifier without Proficiency or bad Ability Modifier plus Proficiency (which tend to come out pretty similarly), and bad Ability Modifier without Proficiency.
In this system, I've simply simplified and formalized it a bit. Your character will only ever use one of three bonuses:
Your Major Bonus represents the things you're exceptionally good or well-trained at. It's equal to one-third your character level plus five, rounded down, and is equivalent to the first category, Proficiency plus a good modifier. Use your Major Bonus for any check you'd normally add your Proficiency Bonus to, and for save DCs-- this is known as Proficiency.
Your Minor Bonus represents raw talent and ability, or perhaps things you've trained at but have no aptitude for. It's equal to one-sixth your character level plus three, rounded down (or, if you prefer, half your Major Bonus rounded up), and roughly corresponds to a Profiency bonus or a good ability modifier alone. Use your Minor Bonus in place of any Ability Modifier or Proficiency Bonus mentioned by your racial features, class features, feats or similar effects. You also use it for two skills and one save of your choice-- this is known as Half Proficiency.
Your Trivial Bonus represents the things that, for whatever reason, you're just not very good at, or things that you really can't train at-- but can, perhaps pick up a bit of luck and practice at over the course of your career. It's equal to one-sixth your character level, rounded down, and is similar to a low ability modifier. Add your Trivial Bonus to any d20 roll that did not already include your Major or Minor bonus, and to AC. Note: Trivial Bonuses can be removed if you want to keep 5e's default of of "no progression at all."
Thus, a character would use their Major Bonus to attack with a rapier they are proficient in, add their Minor Bonus to damage, and then-- when using the Defensive Duelist feat to defend themselves from the counterattack-- add their Minor Bonus to AC against that attack. When they are still hit and dropped to zero health, they will roll a d20 as a death save and add their Trivial Bonus. Later, when attempting to impress a bartender with the story, they will add their Trivial Bonus to the skill check they are not proficient in.
Level
Major Bonus
Minor Bonus
Trivial Bonus
1st
+5
+3
+0
2nd
+5
+3
+0
3rd
+6
+3
+0
4th
+6
+3
+0
5th
+6
+3
+0
6th
+7
+4
+1
7th
+7
+4
+1
8th
+7
+4
+1
9ht
+8
+4
+1
10th
+8
+4
+1
11th
+8
+4
+1
12th
+9
+5
+2
13th
+9
+5
+2
14th
+9
+5
+2
15th
+10
+5
+2
16th
+10
+5
+2
17th
+10
+5
+2
18th
+11
+6
+3
19th
+11
+6
+3
20th
+11
+6
+3
Saving Throw Changes
Obviously, without Ability Scores to turn into saving throws, 5e's save system is basically nonexistent. Luckily, resurrecting the classic three save structure is simple.
Fortitude is raw physical power and resilience, and covers all Strength and Constitution saves.
Reflex is raw speed and coordination, and covers all Dexterity saves.
Will is raw mental power and resilience, and covers all Intelligence, Wisdom, and Charisma saves, as well as Constitution saves to concentrate on a spell.
Alternately, one could keep the six-save split, and simply match each Ability to a skill, like so
Strength -> Brawn
Dexterity -> Acrobatics
Constitution -> Athletics
Intelligence -> Investigate
Wisdom -> Presence*
Charisma -> Insight*
The downside of this is that the aforementioned skills become somewhat more valuable than their compatriots. I think this would work out alright, as the major saves (Dex, Con, and Wis) also match to somewhat skills, but it's also harder to remember and means different characters will have widely differing numbers of good saves, so for now I'm avoiding it.
*Wisdom saves are about self-control and willpower, and Presence is raw strength of character; Charisma saves are about overcoming glamour and charm, and Insight is about recognizing such things.
Skill Changes
The vanilla 5e skill list is actually quite good, and you can certainly use it without alteration. However, there were a few areas it chose to not quite cover. And while I was at it, I figured I might as well edit it a bit more to better consolidate and redistribute competencies, and to replace Tools with something hopefully a little less vague.
We'll start with the loses:
Athletics isn't gone, but it loses its "brute force" options-- shoves and grapples-- to Brawn. In turn, it gets used for a lot of raw Con-type stuff involving endurance. Note: this is the only change that's probably essential
History is folded into a more general "Society" skill, which also acquires raw Int checks' language-type stuff.
Performance is just gone, because seriously, that's what musical instrument tools are for.
Sleight of Hand and Thief's Tools are folded into Thievery; they're related enough, and the latter was significantly more useful than most other tools to start.
Survival is folded into Nature
A new "Presence" skill appears to cover a number of formerly untyped Charisma checks, and take some of the pressure off Persuasion to be the one-and-only social skill.
Tools are gone altogether, replaced by either skills like Thievery (for things like Thief's Tools) or by the broad category of Profession (for things like Artisan's Tools).
And the full list. For reference, the newcomers are Brawn, Linguistics, Profession, Presence, Thievery, and Society, and have been marked in blue.
Acrobatics can be thought of as the "circus skill"-- it covers acrobatic feats, obviously, as well as things like balancing on a sheet of ice, running across a heaving ship, leaping from rooftop to rooftop, and wiggling free of bonds.
Animal Handling covers most interactions with animals, as well as practical knowledge of how to train and deal with them. Calming a horse, training a dog, riding a griffon and raising a bear cub would all use Animal Handling.
Arcana is academic knowledge of magic. It's not enough to let you cast a spell, but it will let you recognize the spells others cast, know how to survive on other planes, identify magical creatures and items, and so on.
Athletics deals with extended physical exertions-- not those that require fine reflexes or huge muscles, but tasks like running, climbing, holding your breath, and other tasks where endurance is important.
Brawn is raw physical power. If you want to wrestle a monster to the ground, topple a statue, or hold up a collapsing ceiling, you need Brawn. Brawn is used in place of Athletics for Shoves, Grapples, and other combat maneuvers. Use your Brawn bonus +10 in place of Strength when determining how much you can lift and carry; thus, your base carrying capacity would be (Brawn bonus +10)x15 pounds.
Deception is all about fooling people. Outright lies, bluffs, disguises, and other cons all use Deception.
Insight can be thought of as a defensive social skill. It's used to read people, to determine their intentions, feelings, and honesty, and to tell if you are being lied to or misled. The DM might also ask for an Insight check to get a gut feeling or hunch.
Intimidation is the violent social skill. It's used whenever you attempt to influence others through threats, violence, and other such actions.
Investigation is the detective skill. Uncovering hidden objects or traps, understanding clues to a crime, following footsteps, and so on all require Investigation.
Linguistics determines how good you are with languages. It's used to puzzle meaning out of languages you are unfamiliar with, understand ancient glyphs, and so on. In addition to the normal effects, you learn two bonus languages if you are Proficient in Linguistics, and one if you are half Proficient.
Medicine deals with both theoretical knowledge of health and the body, and practicalities such as first aid and hospital treatment. You'd use it to diagnose a disease, treat an infected wound, provide long-term care, and similar such tasks.
Nature covers, well, nature. It lets you recognize plants and animals, know which are safe and which are dangerous. It lets you forage for food, lead a party safely through trackless wilderness, read the weather, and so on.
Profession is a slightly odd case, because there is no one use for it. Instead, every time you gain proficiency in Profession, you pick one trade and gain proficiency in that-- Profession (Sailor), Profession (Smith), and so on. You may use Profession to make checks related to your field of expertise, provided they aren't easily covered by another skill. A blacksmith might roll Profession to forge a sword, a sailor to plot a course, and so on. Profession cannot be used to replace skills entirely-- a circus acrobat would still need Acrobatics, for instance, and a hunter would still need Nature.
Perception is your ability to see them before they see you-- it's your general awareness of your surroundings and the acuteness of your senses.
Persuasion is all about getting people to do what you want. Hints, honeyed words, forceful commands and polite requests all require Persuasion checks.
Presence is raw charisma and social magnetism. It determines how well you can command attention, make friends, carouse, and other situations where words are less important than behavior. It also determines how good you are at resisting social pressure from other people, such as attempts to persuade or intimidate you.
Religion determines how much you know about gods, churches, cults, and so on, as well as demons, angels, and other beings commonly associated with religions.
Society covers more general aspects of civilization. It represents knowledge of peoples-- their histories, their languages, their cultures, their cities. It represents not just academic knowledge of who warred with who a hundred years ago, but making contacts and understanding local politics, even in places you've just arrived. You might use it to recognize heraldic symbols, puzzle out a letter written in an unfamiliar language, or figure out who in the local government to contact about a goblin invasion.
Stealth covers exactly what it sounds like-- hiding and sneaking.
Thievery determines how well you can pick a lock, disarm a trap, palm items, pick pockets, and similar such feats. It's also a good measure of general hand-eye coordination.
And one special rule, to help cover edge cases: You may attempt a skill you are fully Proficient in to simulate another-- for example, rolling Nature to calm a wild beast, or Persuade in place of Deception-- but you do so at Disadvantage. This is not guaranteed; the DM must approve the substitution.
One could also, I suppose, make weapons into Skills-- say, Simple, Finesse, Heavy, and Ranged-- for more symmetry here. You could even do armor as well, with each type of armor granting some amount of DR, and AC being 10+(your armor skill), or an opposed roll. But then you lose the distinction between combat and noncombat bonuses, which make things like Guidance, Expertise, and even class-based bonus skills more powerful than expected.
Update: Forget the "Profession" stuff; that's probably not worth it. Tossed out Linguistics, too, which was probably too specific.
Combat and Equipment
Initiative is now a special Reflex save-- feats like Alert apply the bonus only to Reflex saves
Weapons add your Minor Bonus to damage
Armor can be left alone, with the usual use of your Minor Bonus in place of Dex for light and medium armor. Though note that doing so does make Heavy Armor somewhat less useful; Scale Mail and Chainmail will be functionally identical, as will Half-Plate and Splint Mail.
Shoves and Grapples use Brawn in place of Athletics; they are opposed by Acrobatics as normal.
Note: There are other ways you could do armor as well. You could toss out the idea of individual armor types and provide static AC bonuses for the three categories: AC 15 for Light armor, 16 for Medium, and 17 for heavy. Characters can add their Trivial Bonus to get some sense of progression, if so desired-- this is most important for light armor. If you go this route, assume that Mage Armor counts as Light Armor, and Barksin and Unarmored Defense count as Medium.
Another alternative would be to simply declare that if you're wearing armor you're proficient in, your AC is 10+Proficiency, with Barbarians and Monks being the only ones "proficient" in no-armor. If you do go this route, though, you should probably provide some sort of special bonus for at least the more "advanced" categories, so that armor proficiency continues to be an actual defensive class feature. Light Armor can remain untouched as the baseline, perhaps; Unarmored proficiency could, say, gain the ability to negate one opportunity attack/round; Medium Armor could... uhh, something, and Heavy Armor could perhaps reduce incoming physical damage by 2+Trivial Bonus, replacing the old feat. Shields could grant the benefits of Defensive Duelist, if you wanted to keep AC numbers from going too crazy. The specific bonus probably need some work, but I kind of like the underlying idea here...
ASIs and Feats
Without Ability Scores, Ability Score increases are obviously not very useful. Instead, whenever they'd normally get an ASI, characters instead gain one of the following benefits:
Gain Half Proficiency in a new skill
Upgrade an existing Half Proficiency in a skill to full Proficiency
Gain full Proficiency in a new Profession skill
Gain proficiency in a single type of weapon or armor
Gain an additional hit die, though no additional hit points-- the extra die is simply available to spend during a short rest.
If you want to use feats in your game (recommended), characters gain either one or two feats at total levels 1, 4, 10, and 16-- two feats that would normally grant +1 to an ability score, or one feat which does not. (Or one feat which would normally grant +1 to an ability score, and one of the above bonuses for an ASI). In place of this, characters can gain one of the following benefits:
Any two of the bonuses for an ASI
Upgrade their half-proficient save to full proficiency
Upgrade their nonproficient save to half proficiency
Gain an additional hit die and the accompanying additional hit points
Resilient, Skilled, and the weapon/armor proficiency feats are removed as redundant.
Character Creation
As per vanilla 5e, characters get their usual skill, tool, weapon, and armor proficiencies, based on their race, class, and background. If the granted skill has been removed, you may instead gain its replacement. In addition
Characters gain Half Proficiency in two skills of their choice, adding their Minor Bonus to checks
Characters may choose to either gain full proficiency in one Profession skill, or Half Proficiency in two.
Characters gain Proficiency in one save, which must correspond to one of the save proficiencies granted by their class. They pick a second save to of their choice to gain Half Proficiency in. They may add their Trivial bonus to the third save.
Optionally, characters may pick up to two nonproficient skills and take a -2 penalty to them, gaining a new Half Proficiency for each skill selected this way.
Races, obviously, no longer grant Ability Score bonuses. Since this makes normal humans pretty awful, all games should allow Variant Humans instead, limiting them to half-feats if concerned about balance or if you do not normally allow feats.
When calculating your hit points, instead of adding your now-nonexistant Constitution modifier at every level, add each hit die's average value minus 1. Thus a class like the Wizard would give you d6+2 hit points per level, the Rogue d8+3, the Fighter d10+4, and the Barbarian d12+5.
When calculating save DCs, use 8+Major Bonus.
Multiclassing restrictions, obviously, no longer apply, much to the betterment of the game as a whole.
Monsters
The beauty of all of the above is that the system's underlying math is totally unchanged. Characters might be a bit more versatile, with all their abilities operating at full potential, but their peak performance is unaffected-- attacks, damage rolls, ACs, skill checks, and so on will be the same. Because monsters are a bit more nuanced (or, if you prefer, inconsistent) than PCs when it comes to, say, attack bonuses, I recommend keeping combat values-- attack, AC, and so on-- unchanged. Add the new saves, though-- one at full Proficiency, one at Half, and one receiving only the Trivial Bonus. You should probably still use Major, Minor, and Trivial bonuses for skill checks, though, using the monster's CR in place of its level when calculating said bonuses.
They're weirdly over-prominent, because 5e says "your raw ability is just as important as your training" (Proficiency)
They're painfully structured, because of the widespread use of arrays or point buy, class requirements, and ASIs
They're... oddly disposable, somehow, when you look at it. Plug in your Proficiency Bonus, or Proficiency+1, in place of any ability score, and the game is almost unchanged.
So anyway, this is round three of my attempts to elegantly turn 5e into a purely skill-based game.
The Three Levels of Bonus
On the surface, vanilla 5e characters have two levels of competence-- either they're adding just their Ability Modifier to a roll, or they're adding their Ability Modifier and their Proficiency Bonus. But all Ability Modifiers aren't the same-- you'll usually have one or two you'll focus on, which will begin as +2s and +3s, and others that you care little about, that will spend your entire career circle around the drain of +0. So really there are three, perhaps four categories: Good Ability Modifier plus Proficiency, good Ability Modifier without Proficiency or bad Ability Modifier plus Proficiency (which tend to come out pretty similarly), and bad Ability Modifier without Proficiency.
In this system, I've simply simplified and formalized it a bit. Your character will only ever use one of three bonuses:
Your Major Bonus represents the things you're exceptionally good or well-trained at. It's equal to one-third your character level plus five, rounded down, and is equivalent to the first category, Proficiency plus a good modifier. Use your Major Bonus for any check you'd normally add your Proficiency Bonus to, and for save DCs-- this is known as Proficiency.
Your Minor Bonus represents raw talent and ability, or perhaps things you've trained at but have no aptitude for. It's equal to one-sixth your character level plus three, rounded down (or, if you prefer, half your Major Bonus rounded up), and roughly corresponds to a Profiency bonus or a good ability modifier alone. Use your Minor Bonus in place of any Ability Modifier or Proficiency Bonus mentioned by your racial features, class features, feats or similar effects. You also use it for two skills and one save of your choice-- this is known as Half Proficiency.
Your Trivial Bonus represents the things that, for whatever reason, you're just not very good at, or things that you really can't train at-- but can, perhaps pick up a bit of luck and practice at over the course of your career. It's equal to one-sixth your character level, rounded down, and is similar to a low ability modifier. Add your Trivial Bonus to any d20 roll that did not already include your Major or Minor bonus, and to AC. Note: Trivial Bonuses can be removed if you want to keep 5e's default of of "no progression at all."
Thus, a character would use their Major Bonus to attack with a rapier they are proficient in, add their Minor Bonus to damage, and then-- when using the Defensive Duelist feat to defend themselves from the counterattack-- add their Minor Bonus to AC against that attack. When they are still hit and dropped to zero health, they will roll a d20 as a death save and add their Trivial Bonus. Later, when attempting to impress a bartender with the story, they will add their Trivial Bonus to the skill check they are not proficient in.
Level
Major Bonus
Minor Bonus
Trivial Bonus
1st
+5
+3
+0
2nd
+5
+3
+0
3rd
+6
+3
+0
4th
+6
+3
+0
5th
+6
+3
+0
6th
+7
+4
+1
7th
+7
+4
+1
8th
+7
+4
+1
9ht
+8
+4
+1
10th
+8
+4
+1
11th
+8
+4
+1
12th
+9
+5
+2
13th
+9
+5
+2
14th
+9
+5
+2
15th
+10
+5
+2
16th
+10
+5
+2
17th
+10
+5
+2
18th
+11
+6
+3
19th
+11
+6
+3
20th
+11
+6
+3
Saving Throw Changes
Obviously, without Ability Scores to turn into saving throws, 5e's save system is basically nonexistent. Luckily, resurrecting the classic three save structure is simple.
Fortitude is raw physical power and resilience, and covers all Strength and Constitution saves.
Reflex is raw speed and coordination, and covers all Dexterity saves.
Will is raw mental power and resilience, and covers all Intelligence, Wisdom, and Charisma saves, as well as Constitution saves to concentrate on a spell.
Alternately, one could keep the six-save split, and simply match each Ability to a skill, like so
Strength -> Brawn
Dexterity -> Acrobatics
Constitution -> Athletics
Intelligence -> Investigate
Wisdom -> Presence*
Charisma -> Insight*
The downside of this is that the aforementioned skills become somewhat more valuable than their compatriots. I think this would work out alright, as the major saves (Dex, Con, and Wis) also match to somewhat skills, but it's also harder to remember and means different characters will have widely differing numbers of good saves, so for now I'm avoiding it.
*Wisdom saves are about self-control and willpower, and Presence is raw strength of character; Charisma saves are about overcoming glamour and charm, and Insight is about recognizing such things.
Skill Changes
The vanilla 5e skill list is actually quite good, and you can certainly use it without alteration. However, there were a few areas it chose to not quite cover. And while I was at it, I figured I might as well edit it a bit more to better consolidate and redistribute competencies, and to replace Tools with something hopefully a little less vague.
We'll start with the loses:
Athletics isn't gone, but it loses its "brute force" options-- shoves and grapples-- to Brawn. In turn, it gets used for a lot of raw Con-type stuff involving endurance. Note: this is the only change that's probably essential
History is folded into a more general "Society" skill, which also acquires raw Int checks' language-type stuff.
Performance is just gone, because seriously, that's what musical instrument tools are for.
Sleight of Hand and Thief's Tools are folded into Thievery; they're related enough, and the latter was significantly more useful than most other tools to start.
Survival is folded into Nature
A new "Presence" skill appears to cover a number of formerly untyped Charisma checks, and take some of the pressure off Persuasion to be the one-and-only social skill.
Tools are gone altogether, replaced by either skills like Thievery (for things like Thief's Tools) or by the broad category of Profession (for things like Artisan's Tools).
And the full list. For reference, the newcomers are Brawn, Linguistics, Profession, Presence, Thievery, and Society, and have been marked in blue.
Acrobatics can be thought of as the "circus skill"-- it covers acrobatic feats, obviously, as well as things like balancing on a sheet of ice, running across a heaving ship, leaping from rooftop to rooftop, and wiggling free of bonds.
Animal Handling covers most interactions with animals, as well as practical knowledge of how to train and deal with them. Calming a horse, training a dog, riding a griffon and raising a bear cub would all use Animal Handling.
Arcana is academic knowledge of magic. It's not enough to let you cast a spell, but it will let you recognize the spells others cast, know how to survive on other planes, identify magical creatures and items, and so on.
Athletics deals with extended physical exertions-- not those that require fine reflexes or huge muscles, but tasks like running, climbing, holding your breath, and other tasks where endurance is important.
Brawn is raw physical power. If you want to wrestle a monster to the ground, topple a statue, or hold up a collapsing ceiling, you need Brawn. Brawn is used in place of Athletics for Shoves, Grapples, and other combat maneuvers. Use your Brawn bonus +10 in place of Strength when determining how much you can lift and carry; thus, your base carrying capacity would be (Brawn bonus +10)x15 pounds.
Deception is all about fooling people. Outright lies, bluffs, disguises, and other cons all use Deception.
Insight can be thought of as a defensive social skill. It's used to read people, to determine their intentions, feelings, and honesty, and to tell if you are being lied to or misled. The DM might also ask for an Insight check to get a gut feeling or hunch.
Intimidation is the violent social skill. It's used whenever you attempt to influence others through threats, violence, and other such actions.
Investigation is the detective skill. Uncovering hidden objects or traps, understanding clues to a crime, following footsteps, and so on all require Investigation.
Linguistics determines how good you are with languages. It's used to puzzle meaning out of languages you are unfamiliar with, understand ancient glyphs, and so on. In addition to the normal effects, you learn two bonus languages if you are Proficient in Linguistics, and one if you are half Proficient.
Medicine deals with both theoretical knowledge of health and the body, and practicalities such as first aid and hospital treatment. You'd use it to diagnose a disease, treat an infected wound, provide long-term care, and similar such tasks.
Nature covers, well, nature. It lets you recognize plants and animals, know which are safe and which are dangerous. It lets you forage for food, lead a party safely through trackless wilderness, read the weather, and so on.
Profession is a slightly odd case, because there is no one use for it. Instead, every time you gain proficiency in Profession, you pick one trade and gain proficiency in that-- Profession (Sailor), Profession (Smith), and so on. You may use Profession to make checks related to your field of expertise, provided they aren't easily covered by another skill. A blacksmith might roll Profession to forge a sword, a sailor to plot a course, and so on. Profession cannot be used to replace skills entirely-- a circus acrobat would still need Acrobatics, for instance, and a hunter would still need Nature.
Perception is your ability to see them before they see you-- it's your general awareness of your surroundings and the acuteness of your senses.
Persuasion is all about getting people to do what you want. Hints, honeyed words, forceful commands and polite requests all require Persuasion checks.
Presence is raw charisma and social magnetism. It determines how well you can command attention, make friends, carouse, and other situations where words are less important than behavior. It also determines how good you are at resisting social pressure from other people, such as attempts to persuade or intimidate you.
Religion determines how much you know about gods, churches, cults, and so on, as well as demons, angels, and other beings commonly associated with religions.
Society covers more general aspects of civilization. It represents knowledge of peoples-- their histories, their languages, their cultures, their cities. It represents not just academic knowledge of who warred with who a hundred years ago, but making contacts and understanding local politics, even in places you've just arrived. You might use it to recognize heraldic symbols, puzzle out a letter written in an unfamiliar language, or figure out who in the local government to contact about a goblin invasion.
Stealth covers exactly what it sounds like-- hiding and sneaking.
Thievery determines how well you can pick a lock, disarm a trap, palm items, pick pockets, and similar such feats. It's also a good measure of general hand-eye coordination.
And one special rule, to help cover edge cases: You may attempt a skill you are fully Proficient in to simulate another-- for example, rolling Nature to calm a wild beast, or Persuade in place of Deception-- but you do so at Disadvantage. This is not guaranteed; the DM must approve the substitution.
One could also, I suppose, make weapons into Skills-- say, Simple, Finesse, Heavy, and Ranged-- for more symmetry here. You could even do armor as well, with each type of armor granting some amount of DR, and AC being 10+(your armor skill), or an opposed roll. But then you lose the distinction between combat and noncombat bonuses, which make things like Guidance, Expertise, and even class-based bonus skills more powerful than expected.
Update: Forget the "Profession" stuff; that's probably not worth it. Tossed out Linguistics, too, which was probably too specific.
Combat and Equipment
Initiative is now a special Reflex save-- feats like Alert apply the bonus only to Reflex saves
Weapons add your Minor Bonus to damage
Armor can be left alone, with the usual use of your Minor Bonus in place of Dex for light and medium armor. Though note that doing so does make Heavy Armor somewhat less useful; Scale Mail and Chainmail will be functionally identical, as will Half-Plate and Splint Mail.
Shoves and Grapples use Brawn in place of Athletics; they are opposed by Acrobatics as normal.
Note: There are other ways you could do armor as well. You could toss out the idea of individual armor types and provide static AC bonuses for the three categories: AC 15 for Light armor, 16 for Medium, and 17 for heavy. Characters can add their Trivial Bonus to get some sense of progression, if so desired-- this is most important for light armor. If you go this route, assume that Mage Armor counts as Light Armor, and Barksin and Unarmored Defense count as Medium.
Another alternative would be to simply declare that if you're wearing armor you're proficient in, your AC is 10+Proficiency, with Barbarians and Monks being the only ones "proficient" in no-armor. If you do go this route, though, you should probably provide some sort of special bonus for at least the more "advanced" categories, so that armor proficiency continues to be an actual defensive class feature. Light Armor can remain untouched as the baseline, perhaps; Unarmored proficiency could, say, gain the ability to negate one opportunity attack/round; Medium Armor could... uhh, something, and Heavy Armor could perhaps reduce incoming physical damage by 2+Trivial Bonus, replacing the old feat. Shields could grant the benefits of Defensive Duelist, if you wanted to keep AC numbers from going too crazy. The specific bonus probably need some work, but I kind of like the underlying idea here...
ASIs and Feats
Without Ability Scores, Ability Score increases are obviously not very useful. Instead, whenever they'd normally get an ASI, characters instead gain one of the following benefits:
Gain Half Proficiency in a new skill
Upgrade an existing Half Proficiency in a skill to full Proficiency
Gain full Proficiency in a new Profession skill
Gain proficiency in a single type of weapon or armor
Gain an additional hit die, though no additional hit points-- the extra die is simply available to spend during a short rest.
If you want to use feats in your game (recommended), characters gain either one or two feats at total levels 1, 4, 10, and 16-- two feats that would normally grant +1 to an ability score, or one feat which does not. (Or one feat which would normally grant +1 to an ability score, and one of the above bonuses for an ASI). In place of this, characters can gain one of the following benefits:
Any two of the bonuses for an ASI
Upgrade their half-proficient save to full proficiency
Upgrade their nonproficient save to half proficiency
Gain an additional hit die and the accompanying additional hit points
Resilient, Skilled, and the weapon/armor proficiency feats are removed as redundant.
Character Creation
As per vanilla 5e, characters get their usual skill, tool, weapon, and armor proficiencies, based on their race, class, and background. If the granted skill has been removed, you may instead gain its replacement. In addition
Characters gain Half Proficiency in two skills of their choice, adding their Minor Bonus to checks
Characters may choose to either gain full proficiency in one Profession skill, or Half Proficiency in two.
Characters gain Proficiency in one save, which must correspond to one of the save proficiencies granted by their class. They pick a second save to of their choice to gain Half Proficiency in. They may add their Trivial bonus to the third save.
Optionally, characters may pick up to two nonproficient skills and take a -2 penalty to them, gaining a new Half Proficiency for each skill selected this way.
Races, obviously, no longer grant Ability Score bonuses. Since this makes normal humans pretty awful, all games should allow Variant Humans instead, limiting them to half-feats if concerned about balance or if you do not normally allow feats.
When calculating your hit points, instead of adding your now-nonexistant Constitution modifier at every level, add each hit die's average value minus 1. Thus a class like the Wizard would give you d6+2 hit points per level, the Rogue d8+3, the Fighter d10+4, and the Barbarian d12+5.
When calculating save DCs, use 8+Major Bonus.
Multiclassing restrictions, obviously, no longer apply, much to the betterment of the game as a whole.
Monsters
The beauty of all of the above is that the system's underlying math is totally unchanged. Characters might be a bit more versatile, with all their abilities operating at full potential, but their peak performance is unaffected-- attacks, damage rolls, ACs, skill checks, and so on will be the same. Because monsters are a bit more nuanced (or, if you prefer, inconsistent) than PCs when it comes to, say, attack bonuses, I recommend keeping combat values-- attack, AC, and so on-- unchanged. Add the new saves, though-- one at full Proficiency, one at Half, and one receiving only the Trivial Bonus. You should probably still use Major, Minor, and Trivial bonuses for skill checks, though, using the monster's CR in place of its level when calculating said bonuses.