On page 145 of the Player's Handbook, regading the heavy armor, it says "Heavy armor doesn’t let you add your Dexterity modifier to your Armor Class, but it also doesn’t penalize you if your Dexterity modifier is negative". The first part I can understand but does it not seem strange to anyone else that being clumsy does not have an impact on your performance if you are wearing heavy armor? It not like you are supposed to sit there and take every hit and pray it does not get through just because it is a heavy armor. Of course you are being restricted a lot so you can't use a Dex bonus but still having your Dex effectively restricted to average at best because of the bulk of the armor and being clumsy (having a negative Dex mod) are not the same thing.
It not like you are supposed to sit there and take every hit and pray it does not get through just because it is a heavy armor.
This is exactly what it is, in my opinion. The armor is heavy enough that dexterity has no bearing on your ability to use it - for better or worse. Strength, on the other hand, which is what chain, splint and plate require, is an important ability, as indicated by the speed reductions for not having the requisite strength. Effectively, I imagine you are a (slowly) walking tank which dexterity has no effect on.
I think the main reason it is done this way (only applying an effective penalty to a positive Dex modifier) is because applying a general Dex AC penalty would be mechanically meaningless.
Imagine if they applied a -3 dexterity AC modifier for heavy armor. As there is absolutely no mechanical distinction between AC from Dexterity and AC from armor (there's no touch attacks, etc.), all this would do is reduce the effective armor class of heavy armor by three. Essentially, it would be no different from simply saying that Platemail has an AC of 15.
Gameplay reasons.
It is a game rule meant to provide variety among the game options - it isn't meant to simulate reality.
For the same reason having a negative str modifier doesn't lower your damage with finesse weapons.
It doesn't make sense that Dex doesn't help your armor save either.... plate armor is not *that* heavy and restrictive. But its for game balance....
Ganymede425 wrote:
AaronOfBarbaria wrote:
Personally, I would add dex penalty to heavy armor AC and as mentioned strength penalty to finnese weapon damage.
that would discourage stat dumping and would add a little dose of realism.
Trance-Zg wrote:
El_Condoro wrote:
Kalani wrote:
Instead of reading it as heavy armor giving you AC 18, think of it as giving AC 23 with a maximum Dex bonus of -5.
Having a moderate Dex (10) doesn't help a plate wearer dodge any better than having a low Dex (5), in exactly the same way that a ludicrous Dex (20) doesn't help someone in medium armor any more than a high Dex (16) would. You've passed the cap at which personal ability means anything.
Saelorn wrote:
evil_warlock wrote:
Saelorn wrote:
There are many, many things D&D doesn't even try to simulate accurately. Ever try to jump 10 feet while carrying a 50 pound backpack? Good luck.
Heavy armor ignores dex so that if someone has fun playing a clumsy character they aren't overly penalized. They're already going to have bad initiative, never be stealthy and fail most acrobatic checks you throw at them. Yes the sword blows are going to hit them far more often, but so what? A (real life) tank is easy to hit, but it's hard to get through the it's armor plating.
To put it another way, do you change the rules to penalize characters who use a different skill as their dump stat? Is the wizard inconvenienced by an 8 strength? The barbarian for a low charisma?
evil_warlock wrote:
Ok guys, I'm not trying to turn this into a " 
death to the heavy armor users " post, just to be clear on this.
Back on the subject now, why wouldn't the medium and light armor users benefit from this too? Why should we impose a penalty on them if they don't have a positive dex modifier? Please don't look for attempts to turn this into a simulation or impose unnecessary restrictions. If you think this is getting out of hand I'm willing to stop this discussion right now. I'm just trying to understand the logic of this design choise. So, I will accept that there should not be a penalty for negative Dex modifier for heavy armor. Why should there be a penalty for the light and medium armor then?
evil_warlock wrote:
Danfmac wrote:
evil_warlock wrote:
Saelorn wrote:
evil_warlock wrote:
evil_warlock wrote:
Saelorn wrote:
The whole purpose of Heavy Armor is so a character can choose to dump Dexterity. Applying negative Dexterity modifiers to the AC of a person wearing Heavy Armor defeats the purpose of having Heavy Armor in the first place.
I've read accounts of knights in armor just beating away at each other, not particularly trying to dodge but hitting each other until their opponent's armor gave way. Of course I wouldn't be surprised if the same sources also claimed that a fully armored knight couldn't mount a horse, so I can't vouch for their veracity.
But the big hulking brute/juggernaut that just soaks up damage and doesn't even try to get out of the way is a pretty common trope, so why discourage it?
evil_warlock wrote:
To be honest, it makes just as much sense for a DEX pentalty to work in heavy armor than it does to NOT work. So I'll go with the one that the rules say.