Well, i'm a big fan as you, but the truth is that, this graphics is poor, and a damage models are too, and the acid effect is not so good.
In coop, when a Xeno jump onto a marine and the others are shooting the Xeno, that's a poor animation, and some sound effect is strange too. I hope the Gearbox will work on the game a lot of, because this will not enough in 2013.