I took a jazz history course with Chuck Israels at Brooklyn College in 1974, and Chuck went on about how brilliant a soloist Thad was. He was talking in terms of melodic/thematic improvisers, who he felt were superior to artists who simply blew on changes, and I think the context was Monk recordings, where he said Thad and Newk were perfect for Monk's music, and he denigrated Charlie Rouse by comparison, IIRC.
One of my favorite Mosaic boxes, actually.