There is an interesting and informative article over on Marc Myers' "JazzWax" blog about the short life, tragic death, and odd times of Swedish jazz clarinetist and shooting star Stan Hasselgard. Myers asks how great Stan was, and how great he might have been. My opinion has always been that Hasselgard would have been the premier bop clarinetist going forward, because he sound was so much better than his contemporaries--he retained the full, relaxed sound of the great swing era players without falling into the pinched, overly refined and locked in classical thing...and the public has shown over and over again that they prefer that big relaxed sound (a la Pete Fountain, Artie Shaw, et al).
Myers brings up the point that Hasselgard couldn't read music and was self taught...but I don't think these hurdles are as large as critics sometimes think. It didn't hold Django back, and there are many stories of jazz musicians learning theory/how to read later in the game (Gene Krupa, Art Pepper, and others). I think Stan would have caught up...he was a fine player with an obviously incredible ear.