I’m not an insider or anything so what I have to say is put together from interviews and such.
It’s very hard to say, because there are so many types of intelligence they could be using. Dane Cook or Carlos Mencia might be brilliant at marketing and business. Were comedians like Gallagher and Andrew Dice Clay out there doing these characters and then discovered by the people, or did they smartly identify a market for a certain kind of gimmick and exploit it brilliantly? Would that itself make them “exceptionally intelligent?” Above average at least, since most people obviously don’t accomplish such feats.
I get the impression from the OP that’s not what he meant though. He seems to be describing stage personae, which should not be used to judge a comedian. That stuff like winks and laughing along with your own jokes and looking like you just thought of something clever, and apparently off-the-cuff ripostes to hecklers is almost always rehearsed or recycled. But they might be excellent performers to pull it off well. Is that its own kind of intelligence?
I can’t credit “exceptional intelligence” to good joke-making… A comedian could spend years putting together a decent act, refining it through trial and error. I should hope anyone could do that if it was their full-time job. At the end of the day it is mostly about delivery. Those people most prolific at coming at stuff from oddball angles like Mitch Hedburg and Emo Phillips could be attributed with brilliance, or as easily with plain mental illness.
Don’t even get me started alternative/indie comedy, which is exclusively the domain of the over-educated and psuedo-intellectual. Actually I have no reason to get started on that, I just want to get a dig in on it.