Something I had spoken with Whist in the past (when he was still working on whistmod) was redoing the defense system, so its less D&D.
Currently the more defense you have, the higher the chance the enemy will flat out miss you with physical attacks. So basically its a type of dodge.
Unfortunately if you do manage to get hit, it does full damage regardless of how much, or little defense you have. I had purposed to make base defense work more like "physical damage reduced by: x". It becomes physical damage reduction by a flat amount equal to your total defense.
Of course to balance that, some enemies damages would increase (some more than others) so that they can break through your armor's defense and damage you. You would then have your only source of evasion coming from dodge, or avoid.
This would do a couple of things...
1) It would feel less random. With the current method you are either taking full damage, or you are taking none. Too much RNG.
2) Health would trickle down at a more steady, but also more manageable rate. Instead of being insta-gibbed from getting hit 2 times in a row due to bad luck, you are now getting hit much more often, but taking much less damage giving you time to react to getting hit.
3) Some stats may become a bit more useful, (not that they aren't useful now..) but things like hit recovery, and block rate, dodge and avoid would be your main methods of minimizing damage sustained once hit.
4) It would allow more items to have dodge and avoid on them, as they will be the only way to actually evade a hit.
5) You could get people playing more traditional class styles like tank, healer, etc for multiplayer if they wanted, since a player's health shouldn't go from 40,000 to 0 in the blink of an eye anymore.