I will say that the AI in the game is definitely odd. The first game had really simple AI, but I think it
worked better because of how simple it was. People would just charge at you or shoot at you, but it seems that all the extra choices that enemies has must be really complex, because sometimes they get confused... and stop. I just end up looking at them funny (

) for a second, and shooting them in their crit spot. They definitely made some good changes such as bandits taking cover or jumping up onto things (they still won't take ladders though). The thing is... it didn't take long for me to find
new ways to game the AI. Bullymogs throwing shit at you? Just put a column-like object in the way. Bullymogs are fine if they can
still see you, but they never take into account if their objects are constantly hitting something. It was rather amusing to see the bullymog throw his snowball against the ice column constantly.
PhysX does add all of the blowing pieces of cloth into the game, which honestly... makes the game harder at times. The flags or whatever tend to obstruct your vision (although they aren't solid and won't affect your bullets) and can make it hard to get someone in your sights. I am glad though that PhysX provides me accurate port-o-potty refuse physics.
I'm already out-leveling the content after doing the one side-mission (Symbiosis). Obviously, I haven't gotten that far yet since I'm only talking about that, but my biggest complaint about that side-area is... it's too damn big. There's only one objective, but they add this
huuuuuuge extra section that really provides nothing more than two badass bullymogs and the hidden vault symbol.