All the dwarves felt like one character to me as well. Perhaps they will focus on a core group and the others will hang out in the background. (Which if I remember correctly is pretty much what happened in the novel) That may not work for me on the screen.
I don't know how they're going to pull this off but I hope they do.
(My spell check is telling me "Dwarves" isn't a word. But "Dwarfs" is? I feel lied to.)