Ups-Wii Wheel is actually kind of fun (but there's still every other control scheme under the sun if that doesn't float your boat).
-Addition of bikes/tricks system adds variety.
-Great new tracks + first console appearance of the Retro Cup (even for Battle Mode stages!) = Good.
Downs-Just about all of the new characters were bad ideas.
-Plenty of stages that would've been great in the Retro Cup aren't there and some that are shouldn'tve been.
-The Mii's voice will haunt my dreams forever.
-
Also, here's how to dodge POW Blocks (apparently--I haven't watched it):
http://gonintendo.com/?p=41542