I would like to see a little more innovation in terms of art and technical achievement.
I've only seen 2 seasons of Darker Than Black, all of Mushi-Shi, bunch of random Fullmetal Alchemist episodes (same with DBZ), first season of Rueni Kension (spelled that wrong :/, and bits and pieces of Vampire Knight, Spice and Wolf, Code Geass and Ghost in the Shell (SAC or something). I understand my view is narrow, but this isn't to say some anime I've seen hasn't been innovative and technically different than the rest. I thought Spirited Away was flippin' amazing and I really did enjoy watching the said shows above, but much of anime to me in general seems to be calculated and generic in terms of design. This isn't to say that their is anime out there that is awesomely innovative, I'm just unaware of it.
Also, a big part of anime and animation in general is a matter of taste and opinion. I for some reason can't seem to like anything Disney makes except for a handful of Pixar films. I also tend to gravity more towards animation that has heavy usage of boldness in terms of visual contrast (like The Boondocks for example or recently Afro Samurai which I just started to watch). I know this is a terrible analogy, but anime watchers also remind me of extreme metal music listeners (like those that listen to Metalcore, Black Metal, Death Metal etc.) To the mainstream a lot of vocals in these sub-genres of metal sound the same, but I and others can easily hear noticeable differences, which is what I am assuming anime watchers can do with different art styles and such (I don't watch enough anime to be able to really differentiate).