The SFA voice acting was very good, in my opinion.
I think they only showed multiplayer in the movie, so there will be a lot of enemies and stuff, I imagine. We'll have to wait to see about the single player, though. As for the graphics, they may improve, but they're supposed to look sort of like that. Nintendo/Namco intends for it to look sort of like the SNES version (except a million times improved) I think.