My main problem with the suit was that it just didn't blend into the atmosphere of the movie as well as I would've liked it to. I know it was supposed to be a high-tech suit in the context of the movie, but try as I might, I couldn't see it as anything else than rubber. It kinda took me out of the movie. I don't care how they do it, but they need to do something to the suit to get rid of the blatant foam latex look. Give it a texture, paint it, whatever you have to.
This goes without saying, but improving flexibility and mobility is always important. This time around, I want them to try and minimize the amount of creasing the suit does. Perhaps applying the suit as pieces of prosthetics could help(?). Luckily it wasn't too noticable in the final product, but when you could see the creasing, it was kind of an eye sore (IMO).
The cowl needs serious work and redesigning. The thing is ****ing ugly. The huge jawbones, combined with the ears curving inward, make him look chunky and (to put it simply) stupid. If ANYTHING is to be changed on the suit, this is the priority. Change the ears, and reduce the size of the jawbones. And like with the suit, work on the flexibility of the cowl. I want to see Batman be able to turn his head, and by that I mean looking over his shoulder (at least).
As for the cape, lighten the color of it so it matches the suit. Also, get rid of the clasps and join the cape together at the collar bone.
Everything else is fine.