This is a damn big update. The core of it though, I dunno, I need more time with it. But it seems to have failed at its initial goal of reducing rainbow builds. There's even more reasons to pile more elements on your weapons. Sure, they've eliminated contradictory effects like burning guys being frozen, or frozen guys starting on fire. But they haven't really removed the reasons for putting 4 different elemental mods on your weapons. They've just reduced the # of effects you get out of it, and moved the proc effect to its own attribute separate from everything else. But that doesn't change the fact that highest damage = most effects, for the most part. In terms of DPS, I think stacking as many elements as you can after you've done the critical ones will still be tops. Half the elemental effects are fluff when guys will be dead in less than 2 seconds. Maybe it will matter more in high level play, where all this stuff will really be put to the the test. (Time to do some Void runs I think.)
If anything rainbow build is more powerful now.
We lost AP damage, but we gained poison mods. Blast (fire + ice) and corrosion (poison + electricity) have no weaknesses at all, so it's like everything is turned into AP damage.
Meanwhile the physical damage split that's supposed to force you to specialize your weapons is a joke. With +360% anti-everything elemental damage, it's meaningless - even with a 100% puncture damage weapon vs infested you only lose something like 10% overall damage.
On top of that, the +physical mods are TERRIBLE, like... unbelievably bad. They only scale off their particular damage (elemental mods scale off total damage) and are only +30% (elemental are +90%) except concussion rounds for some reason which is +60%. On top of that, the physical damage is specialized, unlike the above anti-everything elemental damage. I honestly don't know why these mods exist, they are just noob traps since the only people who will use them are people who don't know better.
I don't know what they were trying to do with damage 2.0, but unless it was to make one uber build that works on every gun vs every enemy (because that's what we got) they failed miserably.
(granted it's still better then the old system where anything that was not AP damage was worthless, I guess)