Well, it's true that we haven't seen anything about the games, nor played it, but personally, it seems rather...stupid.
I mean, Olympics? At least make it something more interesting, with a more unique style of play.
At least all those Mario vs. Sonic people get their wish.
But Mario+Sonic equal bad. If Sonic is going to be slower, doesn't that ruin the main reason to play the Sonic games?
For those of you so negative, just pray that it isn't goofed up down to S1GBA standards.