Why do you people say that BAD helps aerial game? To me, at least, it doesn't.
In SSBM, you have to work hard in order to dodge an attack, because the airdodge puts you in a bad position. That means, you are forced to think in other ways if you want not to be punished. That somehow adds depth.
In Brawl, airdodge doesn't put you in a bad position, but rather in a better position than your opponent, if his aerial is laggy. You can spam shorthops easily because of BAD. It kills edgeguarding: In SSBM pretty much all characters have good options when edgeguarding. In Brawl, only chars with lagless aerials can follow you and punish bad BADs (lol). Also, airdodging has almost no downsides at all (well, you won't kill anyone with it), it's the safest move in Brawl, easy to spam and hard to punish. It's like Brawl shield/roll, but you can't grab them and punishing it's waaaaaaaaaay harder.
As an addition, you can't say BAD is needed for an aerial game. Try playing any other fighting game. Or Melee or SBB64.
I'm not saying MAD is better than BAD, or which should people use. Just something I think.