Armor as damage mitigation?

[Nightgaun7]

I've never liked the way that AC works in DnD, and with a potential campaign in the offing I was thinking about changing it such that there is being missed by an attack, and then there is mitigating or stopping damage from an attack. Has anyone done this for 4E? Any thoughts on the "neatest" solution (in terms of least work to implement)?

[Leewei]

Set a Damage Mitigation value for Medium and Heavy armor. Suggested values are 2 and 4, respectively.

Reduce the AC bonus of this armor by half this amount.

When a character wearing this armor is hit by an attack vs AC, if the attack roll succeeded by less than the Mitigated Value, the damage is halved after all other modifications.

Example: Bob the Fighter is wearing Scale Armor. In the old system, he'd have a 23 AC. In the new system, his AC is 21, with Damage Mitigation 4. A dragon attacks Bob with a roll of 24. Since this hits him by less than 4, the damage is halved after any Resist, Insubstantial, et cetera is subtracted.

[Gilphon]

AV1 has some alternative Masterwork plate armours that gives a small amount of resistance instead of extra AC. You could just adapt that to other armour types.

[e42randy]

I like the idea of adding mitigation, but just make sure to take into account how this affects other aspects of the game. Sorry if I use non-4e terms here, but my experience with this is from MMOs. Who remembers getting block-capped in Warcraft's Cataclysm expansion? ... No one?

One possible outcome is you remove spikes of damage. Without mitigation and all defense based off of chance, your players will go rounds with little damage and rounds where everything lands. Reduce avoidance and add/increase mitigation to defense, and you can expect a certain amount of damage each round. In the MMO example, if the system balanced mitigation and avoidance to produce the same average damage, your tank would *usually* want mitigation over avoidance, so there are fewer spikes for the healers to deal with.

This may be a good thing in 4e, so leaders don't get bogged down using all of their actions healing in a spike round instead of the other stuff they can do--but it also lowers the chance of an "oh sh*t" moment where a player drops. That's part of the thrill for some people. IMO, if you do implement a mitigation system, do something like Leewei suggests, where the impact of it is minimal.