Meta Knight is less defensive and campy than several of the other good characters. I think it would be silly to think that Meta Knight camps more than Snake, Falco, King Dedede, Olimar, or Toon Link. If Brawl were really all about defense with no offense, Meta Knight wouldn't even be good. Seeing as it's probably a safe claim to say that Meta Knight is, in fact, good; it's probably a safe claim to say there is some degree of relevant offense in the Brawl metagame. Any theory about the situation that assumes no offense is probably bunk.
Also, about Seth in SFIV, um... where is the controversy over banning him? I checked the SFIV forums on Shoryuken, and I not only don't see any evidence that he's being seriously considered for a ban, but I don't see any evidence that he's generally considered the best character in the game (he seems to very consistently be ranked below Sagat, much like every other non-Sagat character). If you're referring to the Japanese, I was under the impression the Japanese mostly played in arcades where Seth and Gouken don't exist so I'm not sure we can trust them to evaluate fairly. If I'm missing something let me know, but Seth's legality in SFIV doesn't seem to be controversial or even a parallel case to Meta Knight (since Seth isn't agreed to be the best character by most people).
I'll respond to Eyada later. That's something that will take some time.