Kefka is a better villain than Sephiroth in every way except looks. Judging by "nuff said" you obviously have no proof on why he's ridiculous other than your own opinion. By the way, the clown thing is not good enough as a reason. I'm not saying you can't have your own opinion; it would just be better to say why though.
Had it been some other villain, it probably wouldn't have lasted long. Though you just had to pick Sephy, and now you have over 10 pages of Sephy fans trying to say how he's the best and pages of people arguing how he's not because they probably are sick of all the Sephy fans trying to say he is. Though some people actually did give good reasons.