The legs and wings can easily just be polish problems. Like, pixel peeking at an extremely low quality, likely mid development screenshot isn't convincing. Alternatively, again, a shifting artstyle, which is not unusual for blizzard at all, come on. We went from the fields of elysium to high technology in a single expac, neither of which align with the other stylistically.
Uh.... Again. Asset reuse. But even then, we don't know if the final version of this race will have new animations or not. There's no way to tell from all of two screenshots. Your evidence is not convincing me.