Quote Originally Posted by Bolivar
"Because, he's an evil clown" just doesn't hold up to the background stories of Sephiroth, The Sorceress, Kuja, or Sin.
A villain doesn't need a ten thousand word backstory to be an decent villain. In the case of Kefka, him prancing around doing a tone of evil s@#$ with childish glee is enough to make him a very effective antagonist.