Have you played Brawl on a real Wii? On real hardware, the controls definitely feel different from Melee; it takes some getting used to. Melee is in general faster paced than Brawl and the controls in Brawl are a bit "looser" than Melee. It may be that you're just having trouble adjusting to how different the games are. Going from Smash Bros. (N64) to Melee is a similar "shock" for those that remember the early days of the Gamecube.
Can't speak for Super Mario World, but NSMB Wii feels just fine if you've played the original NSMB on the DS.
Can't speak for Super Mario World, but NSMB Wii feels just fine if you've played the original NSMB on the DS.