Well, you probably knew that Johnny was a big jazz fan (and played the drums) so I think he was probably the main instigator in booking jazz musicians.
I've long wished they would put out a DVD set of the band and guests over the years. There were many great players who appeared, and often Johnny would feature just the band. Also, some of the interviews were hilarious- Buddy Rich always shook things up a bit.
I really, REALLY miss that show.