Bringing All My Stupid Ideas Together #2 - The Attribute System

[FreakyCheeseMan]

Continuing my series of posts on the game system I'm working on building from the ground up, we come to the second larger subject, the Attribute System.

Hopefully anyone with an interest in game design will find this interesting, even if only from a "Telling me Why I'm Wrong" perspective.

The System
This system uses six primary stats, as below. Each stat is also it's own defence, like a save - some attacks or spells may target Strength, or Perception, etc. In addition to this, there are two other defensive values, the equivalents of AC and SR - these have a single stat as their base, but other values modify them as well. There is no such thing as an Ability "Modifier" - the "average" for every stat is 0, stats can be negative, and your modifier is equal to your stat.

Strength - Just what is says on the tin. Determines:

Attack Bonus with Medium or Heavy Weapons
Damage Bonus with Heavy Weapons or Power Attacks
Carry Weight (This is actually important)
Grappling Modifier
Defence against attacks that attempt to knock the character over with brute force.

Agility - Again, what is says on the tin. Determines:

Attack Bonus with Light or Ranged Weapons
Initiative Modifier
Dodge Modifier
Added to Physical Defence (The equivalent of AC)
Defence against attacks that just try to touch the character, or hurt them before they can react. (Touch AC and Reflex Saves.)

Constitution - Yep, still just what you'd expect "Constitution" to mean.

Number of Endurance Points, rate of E.P. Recovery
Level of Wound a person can "Shrug Off" (Death/dismemberment occurs at 7 + CON Wounds to any body part.)
Defence against attacks that target your health or endurance directly (Poisons, diseases, certain spells.)

Intelligence - Logical reasoning and ability.

Modifier for Counterspelling Checks
Modifier for Casting Rolls on Complex Spells
Modifier for Casting Checks for Metamagic, Etc
Modifier for numerous skills (Knowledge, etc.)
Base Value for Magical Defence (Equivalent of SR)
Defence against attacks intended to confuse or overwhelm the character's capacity to process them.

Perception - Describes a character's perception and intuition.

Determines who gets to take actions (And how many) in a Surprise Round
Determines rate of Mana Regeneration for Spells
Casting Stat for Divination & Illusion Spells
Modifier for several important skills (Sense Motive, Spot, Etc.)
Defence against that rely on fooling the character, or the character not being aware of them - sneak attacks, illusions, etc. (This is crucial.)

Charisma - Determines a character's force of will, personal magnetism and sense of self. This is not the same as how likeable a character is.

Determines the maximum amount of Mana a mage holds at any given time.
Casting Stat for simple, direct effects (Blasting, some defensive spells or force effects)
Casting Stat for spells that attempt to directly impose the caster's will upon the target (Enchantments)
Modifier for Intimidation rolls (But not Bluff, and probably not Diplomacy)
Defence against fear effects, or spells that attempt to directly overwhelm the caster's mind (i.e., most Will Saves)



Why I Did It This Way
First, I wanted to (at least attempt to) eliminate the concept of a "Dump Stat" for any build - while characters should still be functional with negative modifier, it should always be something that costs them (unlike in 3.5, where most builds could have a 6 to Charisma without really noticing it.)

I'm also trying to keep the stats roughly balanced in terms of the basics of what they give you - I'll let you all be the (preliminary) judge of whether or not I succeeded. Obviously some stats will be more important to certain classes/builds, but hopefully the base line is about the same.

Finally, I'm trying to reign in the power of casters from the word go (because I know they'll get stronger as I add more to the game - there's simply a wider range of stuff that Casters can realistically do.) As part of that, I'm intentionally making all of the Casting Classes MAD - it seems only fair, especially as the Martial Classes already are.

Context
Handful of things to hopefully make things make sense in the context of the larger game.

First, it's not a d20; even single-point bonuses are highly significant.

Game uses an "Action Points" system to describe what you can do on a given round - Action Points have three Flavours, Physical, Movement and Thought. Action Points renew at the end of your turn.

Off-turn, you can use certain "Active Defences" to protect yourself against attacks - blocking, parrying or dodging physical attacks, or dodging or counterspelling magical attacks. Doing so will generally let you avoid the attack, but will also leave you with fewer Action Points to spend on your own turn.

Game does not use HP - rather, it uses a wound system. For a character with 0 CON, any body part can take seven levels of wound before it is effectively destroyed; the first three amount to minor bruises or light cuts, and are assumed to automatically heal once you get out of combat. For characters with a high CON, the bonus "Wound Points" they get follow the same category - so, a character with a CON of 3 could take six levels of wound and shrug it off, while that same attack would kill/incapacitate a character with a CON of -1.

The game does *not* use Vancian Casting, because I hate Vancian Casting. Rather, it uses a Mana system (Think Psionics). Characters have a total amount of mana availble to them, a maximum amount of Mana they can spend on a single spell, and a rate of Mana regeneration. (Even with negative perception, mages are assumed to fully regenerate Mana outside of combat, and do not "Bleed" Mana in combat.) Metamagic increases the cost of casting a spell, and applied a Casting Check DC (based off of Intelligence.)

Martial Classes use "Endurance Points" to pull off assorted attacks - Endurance Points work in a similar way to Mana, except they're keyed entirely off of Constitution, and are generally far less limiting. Several spells and attacks target Endurance directly, and characters reduced to negative Endurance points will suffer penalties or even be knocked unconscious.


I think that covers it. What do people think?

[Foxwarrior]

So, you split Will saves into three different ability scores, so it's no longer reasonable for a noncaster to even try to get good at them.

If damaging attacks and explosions are important things in this game, then casters are dependent on every Attribute except Strength, while noncasters can dump all the mental Attributes.

Also, Constitution is still boring, and you neglected to mention any skills for Strength or Agility.

[FreakyCheeseMan]

So, you split Will saves into three different ability scores, so it's no longer reasonable for a noncaster to even try to get good at them.

...technically. The effects are very different, though - the absolute "Make you do as I command/turn on your allies" stuff is all Charisma, so save-wise, it's the most important - as Will Saves go, Perception would just mean believing an illusion, not being compelled to act in a certain way - I think most people would find that less damaging.


If damaging attacks and explosions are important things in this game, then casters are dependent on every Attribute except Strength, while noncasters can dump all the mental Attributes.

Actually, casters would also be dependent upon Strength, for carry weight and armour - a strong caster could pull off decent armour or carry back-up potions, rods, etc. into battle.

Noncasters are at the very least dependent upon Intelligence and Perception. With a low intelligence, they'll be more vulnerable to spells (as Intelligence forms the basis of Magic Defence, the equivalent of SR); a low Perception, meanwhile, would leave them open to Sneak Attacks, and decrease the chances of them getting to act in Surprise Rounds. Charisma... is less valuable, arguably, but does still get most of the stuff from Will Saves.


Also, Constitution is still boring, and you neglected to mention any skills for Strength or Agility.

Constitution gives Endurance Points, which lets fighters use more and more interesting combat manoeuvres. Past that... "Boring" is sort of an ill-defined term. A high Constitution means you can take more damage without it slowing you down, which lets you play in a riskier fashion, stay in fights longer, etc...

Still deciding exactly how I want skills to work - never really liked the system in 3.5. With the exception of the really obvious ones (Intelligence to Knowledge; Perception to Sense Motive), they may not be bound to attributes at all.

[Foxwarrior]

+1 to a Defense only matters against people who can't really attack other Defenses instead, but +1 to an Offense only fails to matter when there's something that Offense can't be used to attack. A Strong barbarian with a giant, poisoned axe can variously attack defenses provided by Strength, Agility, Constitution, or even Perception with the element of surprise. Given that, you'd need some serious cost ramping for people to be able to afford stats that have only defensive value.

It would be more accurate to say that "in my system, noncasters are dumb and easily tricked" than "noncasters are dependent upon Intelligence and Perception". Leave the surprise rounds to those people who also get to cast spells forever and fill the land with lies for no added cost.

[Just to Browse]

What fox said, and also I don't want to track HP, EP, MP, action rate on top of initiative order, and yet another two defenses. Video games aren't even that fiddly.

EDIT: AND called shots.

[FreakyCheeseMan]

+1 to a Defense only matters against people who can't really attack other Defenses instead, but +1 to an Offense only fails to matter when there's something that Offense can't be used to attack. A Strong barbarian with a giant, poisoned axe can variously attack defenses provided by Strength, Agility, Constitution, or even Perception with the element of surprise. Given that, you'd need some serious cost ramping for people to be able to afford stats that have only defensive value.


...what?

We're talking about dump stats - having a -1, 2 or 3 to a defence means that you'll have an easy opening for people to attack, making you more vulnerable. Remember, you decide what attack you use, and can pick your best one; your opponent decides what defence he'll target, and will go after the worst (once he knows what that is.) So, utterly tanking your Intelligence, Perception or Charisma will leave your opponent with an easy way to go after you; this may be something you decide you can tolerate, or make up for with other abilities, but it's still a real cost that you have to contend with (as opposed to 3.5, where, again, most classes can dump charisma and hardly even notice it.)

Admittedly, the system so far mostly gives defensive attributes to most of the stats - this is intentional, as defences are the thing you can't ignore (while it's easy enough to for a wizard to say, f'rinsance "eh, I don't need Strength, I'm not going to be hitting people with sticks anyway.") I would like to have ways each class could turn a high attribute to their advantage (so a fighter who happened to have a high INT score could make it work for them, for instance), but I expect that'll mostly come with specific feats/abilities/class features.


It would be more accurate to say that "in my system, noncasters are dumb and easily tricked" than "noncasters are dependent upon Intelligence and Perception".

...again, not really. What I'm really saying is more like "Dumb noncasters are vulnerable to spells" and "Imperceptive noncasters are easy pickings for rogues" - saying "in my system, noncasters are dumb and easily tricked" is just repeating your own assumption.


Leave the surprise rounds to those people who also get to cast spells forever and fill the land with lies for no added cost.

I'm not sure what the "Fill the land with lies" part is referencing, but the rest of it isn't entirely accurate either.

First, mages still have to conserve resources over the course of a fight, I'm just trying to avoid the whole "5-minute adventuring day" option. As far as conserving resources across the entire day goes, I imagine mages using some of their carry weight (which, as before, I'm actually trying to make significant) to carry the equivalent of scrolls, potions of mana, etc.

As for "Leave the surprise rounds to the casters"... even just in 3.5, surprise rounds can be hugely important, there's no good reason why non-casters would want to surrender that territory unless they're willfully striving for mediocrity.

[Just to Browse]

What fox is saying is that since everything is now important, you now either boost every single defense or you don't boost any. Because when you're in a fight and your perception score is -3 while everything else is +1, the enemy is going to slam spells against your perception defense and you will be left wondering why you bought up your Con to +1 instead of just getting another +1 to hit and damage, because at least then you'd be more effective when you could act.

By tying a defense to every stat, you make players think "well my DM knows my stats and will either beat me like the paper tiger I am or he'll be nice to me" and they'll just dump the others too. It's human nature to gamble over losses, and making a system that encourages it is just going to get the opposite effect of what you want. Rocket Launcher tag for everyone!

The rest is pretty much him repeating what he said.

[FreakyCheeseMan]

What fox said, and also I don't want to track HP, EP, MP, action rate on top of initiative order, and yet another two defenses. Video games aren't even that fiddly.

EDIT: AND called shots.

So, a few notes on that one.

Most characters won't really need to track MP, that's just mages - and they won't have to track the morass that is Vancian spellcasting, so it should be significantly easier for them. (You can't say that keeping track of a single number is more difficult than maintaining an entire list of memorized spells.)

EP I'm a little more on the fence about, and may yet strip out, but most of the time, that'll only apply to fighters - for mages, it's more the equivalent of... nonlethal damage. You calculate what it is when you make your character (Some Constant Value + Some Coefficient * CON), and then ignore it.

"Yet Another Two Defences" - let's look at that one.
3.5 has AC, SR, Touch AC, Flat-Footed AC, Will Save, Fortitude Save and Reflex Save, for a total of seven defences that can be targeted.

This system has Physical Defence, Magic Defence, and then each individual stat, for a total of eight - only one more. Additionally, most of these are very simple - six of the eight are *just* your core attribute, not modified by anything else, so there's actually fewer total numbers to keep track of. Finally, some of them - in particular Strength and Intelligence - aren't likely to be targeted much, as far as defences go. Strength, for instance, would only really be targeted by things that would cause an Opposed Strength check in 3.5 (which I didn't even list among the seven 3.5 defensive values.)

Action Rate is... both simpler and more complicated than in 3.5. Remember, in 3.5, you already have different sorts of actions - full-round, movement, standard, swift, free, immediate, etc, with assorted rules about how you convert between them. In this system, you have a set three types, and you use them in one of two consistent ways - either you spend them on actions or you reserve them for stances/trances. The only thing that really makes them more complicated is that they change based on your character, but I don't think they'll be too much to keep track of - the values don't change much, except occasionally as you level up, and they're one of the core points of your character.

[Foxwarrior]

I'm somewhat in favor of combining EP and MP; that was probably my favorite part of Eragon.

Back to the topic of defenses for a bit. Consider this simplified example: Mister Stabsalot has a +2 in one particular attack, and the corresponding defense; Joe Average has a +1 in every attack and defense. When Mister Stabsalot attacks Joe Average, he is at a net +1 to hit. When Joe Average attacks Mister Stabsalot using any attack other than Stabsalot's favorite, he is at a net +1 to hit. So, in this situation, they're balanced out: when Mister Stabsalot got +1 to a single attack and defense at the cost of -1 to every other attack and defense, he got a fair deal.

So, instead of focusing on giving each stat some sort of defense, I would be more enthusiastic about giving each stat some sort of unique offensive use: that casting triumvirate you've got going there is nice, with potential for all sorts of distinct distributions.

[FreakyCheeseMan]

What fox is saying is that since everything is now important, you now either boost every single defense or you don't boost any. Because when you're in a fight and your perception score is -3 while everything else is +1, the enemy is going to slam spells against your perception defense and you will be left wondering why you bought up your Con to +1 instead of just getting another +1 to hit and damage, because at least then you'd be more effective when you could act.

Okay, it makes more sense when it's phrased that way - but in some ways, it seems like you're making my argument for me; when you dump Perception, you pay for dumping Perception. The question with that build is not why Con is +1, but why you've dumped perception to begin with. Additionally, even in that build, you're still deriving a huge benefit from CON - it's deepening the pool of damage you can take without it slowing you down, which is important (and CON is just about the only source of such.)



By tying a defense to every stat, you make players think "well my DM knows my stats and will either beat me like the paper tiger I am or he'll be nice to me" and they'll just dump the others too. It's human nature to gamble over losses, and making a system that encourages it is just going to get the opposite effect of what you want. Rocket Launcher tag for everyone!

Couple other notes.

First, again, there aren't really particularly more "Relevant" defensive stats than in 3.5; each attribute is a defence, but some of them are more important in that regard than others. "Intelligence," in particular, would be targeted by... next to nothing, and is only really defensively important as a component of Magic Defence (the SR equivalent.) Strength, likewise, would only come up in the sort of situations that 3.5 describes with an Opposed Strength Check - I'm just trying to keep all of the die rolls on the attacker's side, for simplicity. "Perception" is more important, but it's still very similar to, say, Spot and Listen from 3.5 protecting you from surprise rounds.

Second, most builds and enemies aren't gonna be able to target every stat, at least not with their best attacks - so, even if you've embraced having something as a dump stat, having a second dump stat is still gonna be relevant, as it increases the chances of any particular enemy's best attack targeting your worst defence.

Also... even assuming every DM falls into one of the two meta-gaming extremes you listed, there's still the fact that you're part of a party - what's strong against one member may be weak against another, etc. For solo games it's riskier, but solo games are *always* like that.

[FreakyCheeseMan]

I'm somewhat in favor of combining EP and MP; that was probably my favorite part of Eragon.

I remember that from Arcanum, and it worked well there.. not as big a fan of it here, though, for a few reasons. Honestly, I'm more likely to just drop EP - still deciding where it falls on the complexity vs. fun scale.

[/QUOTE]Back to the topic of defenses for a bit. Consider this simplified example: Mister Stabsalot has a +2 in one particular attack, and the corresponding defense; Joe Average has a +1 in every attack and defense. When Mister Stabsalot attacks Joe Average, he is at a net +1 to hit. When Joe Average attacks Mister Stabsalot using any attack other than Stabsalot's favorite, he is at a net +1 to hit. So, in this situation, they're balanced out: when Mister Stabsalot got +1 to a single attack and defense at the cost of -1 to every other attack and defense, he got a fair deal.

So, instead of focusing on giving each stat some sort of defense, I would be more enthusiastic about giving each stat some sort of unique offensive use: that casting triumvirate you've got going there is nice, with potential for all sorts of distinct distributions.[/QUOTE]

>_> I think your example may be a little too simplified, as I'm having trouble seeing how it relates to my system (As most of those stats do not explicitly target anything, particularly not themselves.) - or are you proposing it as an entirely different alternative?

If it's the former, the analogy falls apart in a number of ways. First, as mentioned, stats do not have particular stats that they target (except for some of the spell stuffs - Charisma would target Charisma for compulsion effects, Perception would target Perception for illusions - but, Perception could also be used to keep up more sustained buffs and engage in melee, or Charisma could be used to throw fireballs that target Agility.) Also... I really imagine the situation having a lot more to do with what's targeting what than just the stats themselves. Terrain, positioning, enemy force composition (Fooling the grunts with illusions isn't as good if they've got a keen-eyed commander to point it out), all of those should have a major effect on things as well.

If it's the latter... assuming those two options take about equal points to invest in, it's balanced from a purely numeric point of view, sort of - but it's also not that interesting. I want characters to have a lot of variety, and that means that they do different things in combat - if everyone is making attacks with every stat (some of which don't even make sense - what are you going to attack with Con) it seems like characters will be badly homogenous.

[Just to Browse]

I've repeated the point twice, so I'll just sum this one last time and leave the thread, because I don't think you're going to agree with me no matter what I say.

The point is that is a player dumps any stat then they might as well dump every stat. This may not be necessarily true in every situation, but your current stat setup makes a very strong incentive for that course of activity, and it nets very little compared to letting players dump a stat or two and keep their defenses high.

You can't even say "well the DM will just metagame if he knows your stats" because of course the DM will metagame. S/he is already metagaming by knowing your CR and giving you fights appropriate to that CR. There's literally no way for the DM to write a battle for a party without at some point recognizing that certain people will benefit more/less than others.

On defenses: Touch AC is AC with a penalty. Flat-footed AC is AC with a penalty. I'm assuming that your system has some sort of penalty to Physical defense for being surprised or some dexterity penalty for being stuck in goo, but if it doesn't then that's another complaint I will lodge against it. D&D has SR (if you even get it), AC, 3 saves, (5) not counting miss chances and conditional defense changes and one of them is basically level + 10. This game has 8 defenses without counting the same things. If we add things like evasion, you get an even larger disparity between the two systems.

Those are the opinions I've got for you. If you don't think those things are true or don't think they're bad for your system, then keep on using them. All I can tell you is that's how RPGs work and unless you bend over backwards or taking a 4e-style nerfbat to a bunch of common game components, any end-product is going to be viewed pretty much the way I describe it.

[FreakyCheeseMan]

The point is that is a player dumps any stat then they might as well dump every stat. This may not be necessarily true in every situation, but your current stat setup makes a very strong incentive for that course of activity, and it nets very little compared to letting players dump a stat or two and keep their defenses high.

...I've rebutted that several times. Again, there aren't effectively more defences than in D&D; enemies won't be able to target any defence at will; and attacks against different stats hurt you in different ways (so having a low Intelligence opens you up to a much different set of Bad than having a low Charisma, Fortitude or anything else.)


You can't even say "well the DM will just metagame if he knows your stats" because of course the DM will metagame. S/he is already metagaming by knowing your CR and giving you fights appropriate to that CR. There's literally no way for the DM to write a battle for a party without at some point recognizing that certain people will benefit more/less than others.

There's a big difference between "Level-appropriate Encounter" and "DM will Always/Never put you up against foes that target your weaknesses," which was what you were describing.


On defenses: Touch AC is AC with a penalty. Flat-footed AC is AC with a penalty. I'm assuming that your system has some sort of penalty to Physical defense for being surprised or some dexterity penalty for being stuck in goo, but if it doesn't then that's another complaint I will lodge against it. D&D has SR (if you even get it), AC, 3 saves, (5) not counting miss chances and conditional defense changes and one of them is basically level + 10. This game has 8 defenses without counting the same things. If we add things like evasion, you get an even larger disparity between the two systems.

Several of those fall under the "Active Defences" part, which are actions you take to negate/avoid damage, not just defensive stuffs; things like "Stuck in goo" or "Surprised" function by making it so you can't use active defences - they're very important, but not more numbers that you have to keep track of. Miss Chances are just factored into Physical Defense in this system (the probabilities work out more-or-less the same anyway.)

Also, you completely ignored the point about how some of the "Defences" in my game are very rarely used - see "Strength Defence = Opposed Strength Checks." I'm just using the same system for all of them for the sake of simplicity - and because there's no difference between the base stat and the defence value, there are exactly 0 more numbers that you need to keep track of.

If you count the things that are actually, commonly used as defences, you've got Physical Defence, Magic Defence, Agility, Constitution (barely), Perception and Charisma. Even by the most narrow definition of 3,5 - AC, SR and 3 saves - this is only one more, and it's actually easy to keep track of, as you don't have the save modifier thing.

EDIT: Oh, and I'm pretty sure that no one looks at 3.5 and thinks "Well, I've got a low Will Save; may as well tank my AC too, cause I'm clearly incapable of defending myself anyway," which seems to be what you're proposing people will do.

[FreakyCheeseMan]

Hmm... so... upon further review, yeah, I'd like to add more to the Mental skills for the martial classes - right now they're pretty much *just* defences, plus the capacity to act in surprise rounds.

I figure I'll shift Ranged Attacks to Perception (Agility has a lot already), at which point I feel like Perception is nicely balanced, but... does anyone have any ideas for things I could give Intelligence or Charisma? (I'll use Int to Skill Points if I have to, but I'd much rather come up with something else.)

[Sylthia]

It a nice system, but I think there is a happy medium between "One stat to rule them all" and everyone should be MAD. Making Charisma actually matter is nice, but I don't want to have a system where I can't put an 8 or the equivalent into one or two abilities and completely cripple myself.

I may have misread it, but what do you mean by the Int save? From my understanding, it might make more sense to lump that together with the Cha save, or even the perception one. It seems like Int has enough going for it without it.

[FreakyCheeseMan]

It a nice system, but I think there is a happy medium between "One stat to rule them all" and everyone should be MAD. Making Charisma actually matter is nice, but I don't want to have a system where I can't put an 8 or the equivalent into one or two abilities and completely cripple myself.

Technically, in this system having an 8 in one or two abilities would probably mean you were a dragon. 0 is average; 3 is about as high as humans get. :smalltongue:

But, yeah, and I don't think I've really made any character with a few low stats crippled - hopefully, they just have some shortcomings they need to be aware of. (Try not to let yourself get flanked if you have a low Perception; avoid the front lines or wear heavy armour if you've got a low Agility; try to get some elemental resistances to make up for your low Magic Defence if you've got a lot Intelligence; etc.) I really won't know without playtesting, though, and we're a ways away from that yet.


I may have misread it, but what do you mean by the Int save? From my understanding, it might make more sense to lump that together with the Cha save, or even the perception one. It seems like Int has enough going for it without it.

So, while working on this, I was thinking about the way saves work and the like, and it occurred to me that it might actually be simpler to cut them out entirely, and just have the attributes themselves be targeted. (So, rather than "There are three stats that correspond with three different saves, that you add numbers to, and different attacks target each" just have "Attacks target one of your attributes directly.")

For some of them - in particular Charisma, Agility and Constitution - it was pretty obvious what they'd target. For Strength, there wasn't as much, but it was simple enough to use that in place of Opposed Strength Checks. Perception was a little trickier, but I like the idea of Sneak Attacks actually having to take advantage of the target being unaware of them.

Intelligence... was the odd one out. I listed examples for clarity, because I wanted to explain what sort of things would target each, but Intelligence is certainly the least important; I can imagine... two or three specific abilities, off the top of my head, that might target it. (One would be a flurry of feints sort of operation, intended to get a single attack in past active defences; one would be the same sort of thing only magically, bombarding your opponent with "Empty" spells in order to exhaust his Thought Actions processing them; the last would be trying to put some sort of a "Lock" on their casting ability, where they'd have some sort of mental "Knot" they'd have to untangle in order to cast again.)

But yeah, I probably could drop Intelligence entirely as a defence, but I honestly feel that would be more complicated - remember, these "Defences" aren't like saves, there's nothing else in them; they are literally just the attribute itself, and "Attacks may target any one of your six attributes" takes less time to say than "Attacks may target any one of your six attributes, except intelligence."

[Nightraiderx]

A couple of ideas to throw at you:
The way you could use intelligence for combat is for it to give a bonus to combat related manuevers (trip, disarm, feint) so that a barbarian type (3 str -1 int) would actually have a penalty to use special combat manuvers unlike the savy swashbuclker that put more in int so that he can disable those kinds of combat manuevers easily.

Instead of having one stat for one particular defense, maybe have intersecting choice depending on what one has to encounter.

For example in 3.5 bullrush could be countered by stopping the foe (strength) or side stepping out of the way (agility)

that way it doesn't make it as punishable to have a weakness in one way or another.

Examples:
Fireball (Area effect) is coming at you: you can evade using agility, or resist it using will power cha.

Illusion type effect: detect it using perception, or figuring it out using Int.

Damage reduction: Using your high str to buy armor or resist naturally using a high con.

Trip,Bullrush, Str : Str or Agility

Feints,Sneak Attacks: Perception or Int

Fear type effects: Cha def only.

Just examples, but if you have some crossing effect people won't feel as vulnerable?