Tanky Rogue idea

[Syruptitious]

So I'm making a rogue and I'd like your input:

The concept is a moderately bulky swashbuckler rogue with good AC and damage through sneak attack and booming blade, as well as the swashbuckler's "taunt" ability. The main point I guess is to pin someone down and keep them fighting you, so swashbuckler is pretty necessary for that as well as booming blade and a decent con score. And as long as they're hitting you some of their damage can be mitigated through uncanny dodge. It's definitely not optimal but I'm hoping it will be alright enough because it seems like a lot of fun. Here goes:

Beginning Scores
Str 8
Dex 15
Con 15
Int 8
Wis 8
Cha 15

Human variant (+1 Cha, +1 Con)
Level 1 feat: Moderately armored - Proficiency with medium armor and shields plus a dex bump of 1.
So scores at level 1 are now:
Str 8
Dex 16
Con 16
Int 8
Wis 8
Cha 16

Strap in, because they're not gonna change until 10.

So level 4 you then take Medium armor master as a feat, which gives no dex bonus (for some reason) and now allows you to add +3 dex to medium armor and medium armor no longer gives disadvantage on stealth. I guess if anything's not totally necessary it's this feat, but I really like it so that's basically the reason I'm taking it. It does give you better AC and you can stealth around in half plate, but whether that's worth putting off ASI's is up to you.

Now then, level 8 things get interesting. Probably at this point you've had some luck as a tank, 20 AC, good damage, uncanny dodge taking care of some of the attacks that get through. But you're horrible with swarms and other characters are gonna start outpacing you quick. So you take an ability score increase right? Of course not, you're in too deep. You're taking magic initiate.

So magic initiate you use the Warlock or Sorceror spell list and take: Booming Blade, Green Flame Blade, and something as your level 1 spell (Armor of Agathys? Something more utility oriented? Not sure on this yet). BB and GFB are (get ready) really really good cantrips. BB punishes the enemy for trying to get away from you, and GFB helps you cleave in big packs of enemies. So now you've got utility as well as damage that (since you're only making one attack per turn) keeps up with the rest of your party.

Finally, at level 10 you may take the ASI and get your dex to 18, then to 20 at level 12. If you are a complete madman you can double down on constitution since your AC is as high as it's gonna get and you want to laugh at the Fighter/Paladin. I only recommend dex because so many of your abilities require attacks to land. Then at 16 and 19 you can take whatever, assuming your campaign even gets that far. I suggest some more goofy feats but that's just me.

So that's basically the idea. by level 10 your scores are:

Str 8
Dex 18
Con 16
Int 8
Wis 8
Cha 16

You have the following feats
Moderately Armored
Medium Armor Master
Magic Initiate: BB, GFB, some 1st level warlock or sorceror spell

Your health is somewhere in the high 70's low 80's. Your AC is 20. You can BB or GFB every turn. Grab a shield, grab a rapier, put on your half plate and challenge every monster to an honorable duel, just be ready with the Uncanny Dodges. Also you have all the other roguey abilities at your disposal, which I've heard are also good.

Let me know what you think, and whether you have any suggestions to make the concept stronger. I definitely want opinions on the 1st level spell from magic initiate. Also if this should be in a more specific thread let me know and I'll move it.

Thanks for reading!

[JellyPooga]

Sentinel is the definitive "sticky" Feat. This goes double for Rogues who benefit immensely from the additional opportunities to get another Sneak Attack. You really want, if not need, this Feat. I suggest taking it in place of Medium Armour Master, which does very little for the build that can't be put off (arguably indefinitely).

[Citan]

So I'm making a rogue and I'd like your input:

The concept is a moderately bulky swashbuckler rogue with good AC and damage through sneak attack and booming blade, as well as the swashbuckler's "taunt" ability. The main point I guess is to pin someone down and keep them fighting you, so swashbuckler is pretty necessary for that as well as booming blade and a decent con score. And as long as they're hitting you some of their damage can be mitigated through uncanny dodge. It's definitely not optimal but I'm hoping it will be alright enough because it seems like a lot of fun. Here goes:

Str 8
Dex 18
Con 16
Int 8
Wis 8
Cha 16

You have the following feats
Moderately Armored
Medium Armor Master
Magic Initiate: BB, GFB, some 1st level warlock or sorceror spell

Your health is somewhere in the high 70's low 80's. Your AC is 20. You can BB or GFB every turn. Grab a shield, grab a rapier, put on your half plate and challenge every monster to an honorable duel, just be ready with the Uncanny Dodges. Also you have all the other roguey abilities at your disposal, which I've heard are also good.

Let me know what you think, and whether you have any suggestions to make the concept stronger. I definitely want opinions on the 1st level spell from magic initiate. Also if this should be in a more specific thread let me know and I'll move it.

Thanks for reading!
Well, considering what your objective was (which was not max AC or max HP or things like that) I think you covered it pretty good.
+1 on Sentinel suggestion though, if you want to make people stick to you it's great. With that said, it does "counter" a bit the Booming Blade if you target the same creature. As long as you use it on another creature, it makes you able to "soft-control" (aka you don't "control" technically what a creature does but you gear its choice by restraining options or making them less relevant) two creatures's movement.
So you could cast Booming Blade on A, Disengage as a bonus action, then go stick to B to force it to attack you because it becomes the "probably best" option (unless it has high enough chance to avoid your OA).

The problem is, where to stick it?
I'd say it depends on how you want to play your Rogue.
- If you plan to stick as much as possible in the middle of enemies, every bit of AC helps so MAM has to be taken early. Then I'd say take Sentinel either after DEX 18, or even before if you have someone in party that can reliably help your to-hit chance.
- If you instead plan to be a true Provocker, staying just far enough to allow only a few enemies to attack you, then I'd suggest swapping MAM for Sentinel at level 4 and keep MAM for later.

To be honest though, if optimization of your concept is really want you want, unless your challenge was optimization of a pure Rogue, I'd say a single level of Fighter (starting or not) is worth delaying Rogue progression: you get medium armor + shields + Defense style (effectively bringing to you the best benefit of MAM), which in turn frees the Variant Human feat for whatever you want (either take MAM or Sentinel now, or grab another good one among Resilient, Lucky, Shield Master etc).
Or, in the same vein, instead of making a single level dip in Fighter, make a single level dip in Draconic Sorcerer: you get similar or better AC in the end, more cantrips (Booming Blade, Shocking Grasp, Ray of Frost, Minor Illusion), several spells that can help much in and out of fight (Shield, Magic Missile, Comprehend Languages, Sleep/Silent Image/Fog Cloud) with 2 slots instead of one for the day.

For a pure Rogue, you're pretty much spot-on (apart from the Sentinel thing).

[Syruptitious]

Both of you are right in regards to Sentinel. MAM was, as I mentioned, really just something I'm personally fond of. But really giving up the point of AC in the long run for better utility with Sentinel seems absolutely worth it. I do want to keep it pure rogue, so taking a level in Fighter or Draconic Sorceror is off the table for this specific character even though they're absolutely ideal for optimization.

Sentinel, however, is definitely worth dropping MAM. If I do want MAM, that can always come later.

Also Sentinel would help in delaying Magic Initiate and instead focusing more on Dex since the character's utility focuses so much on hitting. So now let's look at this with Sentinel

Human Variant:
+1 Con, +1 Cha
Moderately Armored: +1 Dex
Sentinel at level 4
ASI at 8 & 10 straight to Dex

Scores at 10 are
Str 8
Dex 20
Con 16
Int 8
Wis 8
Cha 16

Health is unchanged and AC is 19: 1 point less, but chance to hit is one point higher which is more important to the idea.

Magic Initiate can come at level 12, since BB and GFB are still pretty handy tools.

[Specter]

Medium Armor Master is not worth a feat imo. Grab Sentinel instead.

Also you definitely don't want a negative WIS; it governs important skills and a very important save.

[Syruptitious]

Medium Armor Master is not worth a feat imo. Grab Sentinel instead.

Also you definitely don't want a negative WIS; it governs important skills and a very important save.

Yeah, Medium Armor Master is unfortunately something I thought would be more fun than good. Sentinel is much better.

Also for Wisdom I'm going expertise in perception to cover that weakness a little bit, but a low wisdom score's gonna suck any way you cut it. Rogues get proficiency in wis saves at 15, but most campaigns don't last that long. What I might do is bump charisma down to a 14 to start with and get something other than GFB with magic initiate. BB Would still be fine since it's damage isn't tied to a casting stat. That would open my options up to the wizard list and I could grab find familiar or something.

[Specter]

Yeah, Medium Armor Master is unfortunately something I thought would be more fun than good. Sentinel is much better.

Also for Wisdom I'm going expertise in perception to cover that weakness a little bit, but a low wisdom score's gonna suck any way you cut it. Rogues get proficiency in wis saves at 15, but most campaigns don't last that long. What I might do is bump charisma down to a 14 to start with and get something other than GFB with magic initiate. BB Would still be fine since it's damage isn't tied to a casting stat. That would open my options up to the wizard list and I could grab find familiar or something.

Booming Blade is better than Green-Flame Blade for rogues, because with bonus action disengage you can make them chase you and practically force the secondary damage.

[JohnDaBarr]

Had an idea for a similar build a month ago that relies on High Elf for the Booming Blade cantrip:

8, 17, 14, 9, 14, 12 High Elf Rogue Swashbuckler
Lvl 4 Moderately Armored
Lvl 8 Medium Armor Master (if it's possible to get magical +1 light armor then MAM is unnecessary)
Lvl 10 ASI Dex
Lvl 12 Blade Mastery

At lvl 8 that would be 18 Dex, 20 AC, average HP 59 and 2d8+4+4d6 dmg with a Rapier on hit. High AC coupled with Rogues Uncanny Dodge creates a decent tank and damage dealer since the Swashbucklers mobility guarantees extra dmg from Booming Blade.

An upgrade to this idea would be 2 levels of Trickery Domain Cleric. It offers access to Medium Armor&Shield, an impressive toolbox in form of cantrips and lvl 1 spells, good domain spells and two domain abilities any Rogue would sell a kingdom to have!! Advantage to stealth for anyone that lasts up to an hour and 10 rounds of almost guaranteed advantage on attacks per short rest! Even taking 4 lvls looks tempting considering it offers access to Mirror Image and Pass Without Trace plus normal lvl 2 Cleric spells.