Biased against Olimar? I don't see why. Biased towards Sonic? Maybe, but not excessively I think. I play him only slightly more than I play Peach, Ganondorf, Lucario, Meta Knight, Dedede, Falco, Zelda, Charizard, and Sheik.
If it's not here, where is it? You wanted me to discuss what I thought was wrong with the game. It's a little weird to ignore it just because it's not about Sonic. I want to know what other people think about Olimar. Does anyone know a good Olimar player? Is he as obnoxious to other people as he is to me?
As for Sonic's Dair being turned into a meteor...
Moreover, so is the spring. If you want to meteor cancel both, you can just tap jump cancel the first one and up B out of the second one. You'll lose a little altitude, but for most characters you should be fine if you're not too far away horizontally.
As for no risks going for the Dair offstage, that seems very strange to me. Sure, if he does it out of a forward through or whatever and you DI to a place where he can get it while you're unable to act, he'll land it. If you can act, just air dodge. It's Brawl, it doesn't kill you. If you're feeling lucky, throw out a hitbox to trade with it. He'll probably die in the abyss along with you.
Are you getting thrown offstage too much? Get out of the way when Sonic moves in to grab you. If he does grab you near a ledge, DI up and in. Are you being thrown off with aerials? All of them are wacky multi-hit moves and you should be able to SDI clean through Sonic and avoid being thrown off entirely.