Real Time With Bill Maher would actually be my top choice of any show for Al to appear on. (And also it's probably one of the least likely shows he would ever be on.)
Although Al DID appear on Politically Incorrect, back in 1997. The other three panelists were
Stephen Bishop,
Gibby Haynes and
Meshell Ndegeocello, and the topic was Rock Lyrics and what they mean.
Unfortunately, the other three panelists talked so much that Al barely got a word in, and when he did, it was usually a joke rather than a serious observation. Strangely enough, Al wasn't even the weirdest guy on the panel; the obviously baked-out-of-his-mind Haynes (of The Butthole Surfers fame) spent every available moment espousing wildly digressive theories and non-sequitors about Bon Jovi, 1930s Texas blues,
Brian's Song for no reason at all, and at one point he accidentally reveals that he's unfamiliar with the song "Louie Louie."
Al or no Al, it's AMAZING television. It's definitely on my list of things to upload to YouTube one of these days...