Well, there is also the fact that canon characters aren't really... personal for most people. You can have fun with them sure, but you wont be really attached to them as much as an OC for most people. Plus you also have to use their mythos and everything and work around that and all that fun stuff.

I dunno. Most chars that are 'serious' often times don't work so well for comedy. Anime chars have a decent balance for the most part, Ie One Piece, DBZ, and the like, but then those characters are also usually not... well, they're usually stupid powerful. Imagine somene playing Vageta here, lol. team four star does do a good job of making canon fnny though.