Roy Clarke is a very talented performer on many insturments and I take nothing away from him, but before HeeHaw he was a studio and backup musician. Buck was already an established star with a long string of #1 hits.
HeeHaw also had other great musicians such as Jethro Burns , Floyd Cramer, and Chet Atkins (the Million Dollar Band). However, except for the gospel segment humour was more important than perfection, and that is perhaps why it was such a great show.