What's impressive is how he progressed as a player during his time with the Trio. On the first album, he really didn't know what he was doing. He did this bump-titty thing with the 5th string, brush, 5th string. That is extremely limited and unorthodox.
By the time he left in '61, however, he was a very good player for both frailing and non-Scruggs three-finger picking. (Check out Buddy Better Get on Down the Line, With Your My Johnny, and You're Gonna Miss Me). Over on the Banjo Hangout, those guys know their stuff and can be very critical. Nevertheless, they have a great deal of respect for Dave's playing and, as I said, that's a tough audience.
The odd thing is that after the Whiskeyhill Singers disbanded in '62, Dave seems to have abandoned the banjo. There are no recordings/videos etc. of him and the banjo (except for the Reunion Concert where, for some reason, he played a Gibson, not his Vega longneck). I wonder why he gave it up?
The frailing thing is interesting. He frailed with the Cumberland Three but not with the Trio. Could it be that he wanted to avoid sounding like a guy trying to sound like Dave? His post-Trio frailing, much later in his solo career, is really nice. It sounds as if he was playing in some odd tunings.
Unlike Dave or John, he is a real bluegrass player and that has helped give the Trio some real drive on the up-tempo numbers. He can play the fancy stuff, as shown by his work on Rolling River, but on the established Trio numbers, he tones it down so that the banjo fits in the same way as it did with Dave or John.
I love the story about George tearing his hair out trying to figure out the banjo part for Desert Pete only to find out later that Glen Campbell had played it on a six-string banjo in open D.