Would it work with a shield?
I would allow it, so long as the character is proficient with shields.
It might be too powerful for Dex based Warforged if it didn't come with a max Dex bonus. Monks top out at 20 AC with 20 Dex and 20 Wis, but rogues can only get 17 AC with 20 Dex and studded leather unless they can get magic armor.
If magic armor is common in your games, and if warforged cannot get their natural armor enhanced (maybe they are getting magical with their levels), then it would be fine. They'd end with +1 AC more than a rogue with +3 armor or a monk with 20/20 Dex/Wis.
I don't mind this too much, honestly. In part, because if I created a warforged race using this ability, I think I would also add that warforged only get half the benefit of magical healing and normal medicine kits would not work with a warforged. Having such a drawback is not really in the spirit or tone set up by 5e, but it is pretty fundamental to how warforged were designed in 3.5.
Balance aside, it's an elegant mechanic.
Thanks! I thought so as well! ^_^
Its interesting. It would certainly encourage warforged characters outside the usual image such as Monks, Wizards, Druids etc. - You'd need to add the standard rider that this is a separate way of calculating AC, and not a flat bonus.
Its probably not unbalanced over the usual level range of a character.
Yea, I don't think I would allow it to stack with Unarmored Defense. As normal, you would choose which option, not combine them.
At first glance, it looks balanced. However, I'm not sure it works the way you intend it to. This would push warforged into classes that like Dexterity, and eschew Strength - the opposite of a "classic" warforged. While warforged certainly can be rogues, bards, rangers, arcane casters, or monks - that's not really the archetype.
This is definitely a concern, and I'm glad you pointed it out. But I think if we consider warforged in the context of the Eberron setting, while they might excel in some of these other roles/classes, in general they were assigned as foot soldiers, and so a majority of the cannon warforged NPCs would be the martial strength based classes. PC Warforged are supposed to represent the more elite, atypical warforged individuals anyways.
Additionally, from my perspective, mechanics are different from the flavor of what you call yourself or your role in a battalion. So a warforged with rogue levels may have the sneak attack and the improved mobility, but they may be referred to as the skirmishers in the group. Warforged with arcane abilities (Wizard, Warlock, Sorcerer levels) would be perhaps the magical artillery or sniper.
So there's a couple of ways to manage this, depending on how you envision the warforged to interact within your game/campaign. Additionally, if you have different subtypes/subraces of warforged, you could find other ways to indicate racial preference towards more strength based melee type classes.
You could cap the prof bonus based on armor proficiency. Say, none = +1, light = +3, medium = +4, heavy = +6. Because your ability to tinker depends on understanding armor.
This is certainly an option, but I don't think I would utilize it. The warforged were built for combat to be durable and brutal warriors. Those with specialties outside of melee combat would still be designed to be as armored as possible. At least from my perspective, it seems like an arbitrary/artificial limitation placed on the race/ability. It also complicates how it is implemented.
That would still lead to a preference for Dex, since they get full Dex bonus regardless of proficiency.
I'd probably go with something like this:
Inherent armor: Warforged are created with various degrees of armor depending on their intended purpose. At character creation, choose one of these:
* Composite plating - AC 11+Dex, no requirements.
* Mithral body - AC 13+Dex (max +2), must have medium armor proficiency, considered to be wearing medium metal armor.
* Adamantine body - AC 16 (no Dex), must have heavy armor proficiency, considered to be wearing heavy metal armor \m/. You have disadvantage on Dexterity (Stealth) checks.
Upgraded armor: At higher levels, the warforged's inherent armor grows tougher. Increase your natural AC by your proficiency bonus -2.
(The first one or two points of upgraded armor, at level 5 and 9, basically reflect that someone who actually wears armor would upgrade to better armor (breastplate/splint, half plate/full plate) when they can afford it, and only the later increases are supposed to keep up with magic items)
This is certainly an option that would be viable. I'm not surer I would implement it though, simply because the way I view warforged and how they were designed, heavier armor would not restrict their movement in the same ways as a humanoid wearing armor. The armor is their skin, and for me, it doesn't make sense to impose restrictions. I understand from a mechanical standpoint for balance reasons, but I think in my decision making processes I may skew more towards the rule of cool or narratively based decisions.
I love how clean the OP's idea is. What if it was like
"You can use your proficiency bonus instead of your DEX bonus when calculating your AC"?
That is... a really interesting take. It would have the impact of reducing the power/draw of the Dex based characters. The one issue I see is that you would see a lot of warforged with a preference for light armor, which thematically doesn't make much sense from my perspective.
