Yes it was!
Exactly right! More than just being clowns, they're both raw forces of evil. No rime or reason for it other than sheer enjoyment. The lack of depth in this case is actually what is essential to their greatness. To tack it back even further than the Joker, Kefka is the Loki character, pretty much the inspiration for all scary jesters.
Edit: To add before someone feels the need to point it out, I'm aware Kefka did have a goal in the game. That was plot, I'm talking about character.





