I like Keenan myself - but sometimes I do think he is missing part of his humor without Kel. He was half of the Keenan/Kel duo on Nickelodeon - "The Keenan and Kel Show" and "All That."
Still - my favorite role he's played was Fat Albert in the movie of the same name. He is one of the few people who has played an iconic role (here a cartoon character but still an iconic character) the way the character was designed, and it only made the movie good.
Personally the only actor was I WAS glad to see go was Norm MacDonald - he became way too full of himself and it showed in his performances.