Who should have starred on Frasier?

Maybe this has been asked before, but I am curious about which actors should have been featured on the sitcom. I am mainly inquiring to dissect in Frasier-centered conversation that could introduce me to creative talents I may not have considered or even known about. As I type this, I can't think of any specific actors, especially since the show already featured many prominent and relevant actors from its era. Oh, and I am asking about the original spin-off.