Should natural armor and other armor bonuses to AC stack?

[Endarire]

Greetings!

The question is right what it says on the tin.  To elaborate, saying "No, they shouldn't stack," means that, for a creature with natural armor (like a Kobold) who also either wears armor (like a chain shirt) or gets an armor bonus from another source (mage armor, et al) will use the highest armor or natural armor bonus to AC.

I ask this because, after seeing what a low level character can amass in AC due to alter self, mage armor, and the like, I wonder if they should stack.  (Mind you, in 3.5, they probably should, just to keep AC having some value in mid- and late-game.)

[SorO_Lost]

Flavorwise? Tough skin protects the gaps in armor and absorbs kinetic energy better.
Mechanically? Probably. Recall that McFighter can buy constant Natural AC bonuses and Spells are meant for short term bursts, we just seek to break that.

[Empirate]

To be honest, given pure physics, even a lot of armor bonuses to AC should stack. More stuff in between incoming blow and you = less impulse delivered to your skin and inner organs. I don't see why bonuses shouldn't stack, no. A Wizard getting ridiculous AC at low levels with Alter Self plus Mage Armor is still inferior to the Wizard just casting Mirror Image. There's really no problem.

[SolEiji]

Wait...  they already stack.  Armor bonuses and Natural Armor bonuses are two different sources of AC.

Though to answer, logically all AC bonuses should stack (physical ones anyway, magic has different physics behind it) but they don't cause... game balance and stuff, and people attempting to wear multiple layers of full plate.

[RobbyPants]

If I were designing a new game from scratch based on 3E D&D, I might not let them stack, just to help keep things on the RNG, but that would be one change in many that would get introduced.

As far as mucking around with 3.0/3.5, I wouldn't change it. Like pretty much any fix, you get the desired results in some areas, and you make things worse in other areas. Also, you have to recalculate a lot of monster's ACs on the fly. Every fight.

[phaedrusxy]

This is one of the changes in Frank and K's Tome rules that I chose to not use in my games. I understand the desire to keep things on the RNG, but I just don't like this "fix".

Most of the time, the PCs having a high armor class isn't a problem, anyway, and if they go so far out of their way to boost it to where it is, they probably gimped themselves somewhere else.

Typically at the higher levels (in my experience) attack bonuses are high enough that armor class just determines whether your later iterative attacks have a chance of missing on rolls other than a 1 or not, and how much you can power attack for.

I don't mind lower level combats being less lethal, and having relatively high ACs compared to attack bonuses makes them less lethal usually.

So I just don't see the need for a "fix".

[awaken_D_M_golem]

1e had an Armor vs. NA thing going on.
iirc --- Say you had NA+5, you could put
on Leather but it wouldn't do anything.
Put on Chain and get a +1, to make +6 total.
But that all seemed weird with Shields
doing nothing unless the whole package
was big enough.
Now let's throw in the various magical bonuses.

idk the way out of all this // wouldn't hazard a guess.