I would've preferred a new assassin, personally, but I like Ezio.
Provided he doesn't cross completely over into "crotchety old man" territory, like Brotherhood hinted at. As is, he's a really cool old guy.
I've heard rumors that the actual AC3 (not Revelations) might have a Russian protagonist in... well, Russia. That'd be pretty cool. Wouldn't mind feudal Japan, either.