I think this will be one of their big reveals, a trump card! My speculation is they will be more beast like, and more angry looking :verymad:
I hope not! Why should they always look angry? Do cats always look angry? Do lizards always look angry?
Now, WHEN they are angry making them look beastly angry is perfectly fine for me. I'm just not a fan of "this is an anthropomorphic animal race, so they are always angry." The same goes for Orcs, I like depth.
Video of a big cat not being angry:
http://www.youtube.com/watch?v=KoikkboJ_Fw&t=1m20s
As for how they look, I hope of a middle ground between Oblivion and Morrowind. No crazy legs, but more paw-like fingernails and toe nails.