I don't know about "left field apesh*t", but definitely his ability to take it out and come right back in is most indicative of quite a few of his great solos. I'm running over in my head now a couple of pieces of his that have always killed me, "Jinrikisha" from his very first Blue Note-led session, PAGE ONE, and the version of "Blue Bossa" from LIVE IN JAPAN. He was great, and I think despite all the recognition he received during his later Verve period, still somewhat under-rated.
While it may be true that Joe is somewhat under-rated, I think he is quite influential among young up and coming tenor players. I consider his Verve CD's for all their popularity, to be rather over-rated and among his least interesting. Right now I'm listening to Discs 5-8 of the Milestone box, and while I find the music on these discs less than totally satisfying, Joe's playing is EXCELLENT, some of his strongest (and best recorded) I think, and much better than on the later Verve sides.
Yes, while not exactly up and coming tenor players anymore, Joe Lovano, David Sanchez and particularly Javon Jackson strike me as having a huge Henderson influence in their playing. As for a younger guy, I'd add Marcus Strickland to that list.