There's are already a SSBB topic, but what I've heard, is that Gannon is even slower then he was in melee, so I really doubt he would own everybody. I can't really decide on a character right now, but I'll definalty know as soon as the game comes out.
You gotta get lucky with Ganon, if the enemy is far away and fast, Ganon cant touch them. But if someone walks into his attack range, prepare for some punishment.