>>2 has a pretty good point, especially about the FLUDD comparison.

Also, from what I've seen, I think the Rush and the storybook games and I guess unleashed to an extent (haven't played any of them outside of the rush games), Sonic is more or less himself as long as he's not bogged down by other characters.

Of course, this isn't really going into gameplay, but I doubt that was the original intention of the thread. That little movie Sega did was pretty amusing and captured Sonic pretty well, and making him mute again was an interesting twist, if only to make the movie universal. It'd be neat if they could make him mute in another game as well, even if it's unlikely, just to experiment on how far they can take him with gestures and a few sounds alone.