Okay, saw the trailer. First impression?
While I do think that attempts to make a "realistic" cartoon character often make them look much different and almost unrecognizable, this one I'd have to say they did better on.
Compare them - First trailer Sonic on the left, new trailer Sonic on the right:
That being said, Jim Carrey is still not the best choice for Robotnik, but whatever. They're obviously not going to change that before launch. Everything else seems fine. It looks like a funny movie, only I would have liked to see if the other Sonic characters were in it.
EDIT: To emphasize my first point, here's another comparison.
The Smurfs Movie:
Smurfs: The Lost Village:
EDIT 2: Here's a copy of the old trailer, if anyone wants their eyes to bleed: