Rickman clealy had a lot of fun playing villains; apparently he improvised or re-wrote most of his lines in Robin Hood, making it hilarious.
No, it's Leonard Nimoy. This is a Trek TOS satire, and he's the alien sidekick who hates his catchphrase "Live Long and Prosper" or, in this case, "By Grabthar's Hammer, you shall be avenged".
Nimoy had a reputation for being quite sick of being Spock. It was even the title of his biography: https://en.wikipedia.org/wiki/I_Am_Not_Spock
But on the other hand, that might just be an oldish man not really feeling comfortable playing an immature character (that's part of Han's charm, really).
I'd wager his dislike of the Han Solo character had more to do with working with George Lucas.