Don't think anyone has mentioned the 2 (Japanese) Why Not dates, Air Song and Air Raid. These are well recorded, beautifully played dates. India Navigation reissued them in the US.
I'm more than "happy" Threadgill renamed the band after Steve McCall was ousted. It was a different band.
BTW, I'm with Sangrey about all of Threadgill's music. For me he's one of a number of guys (in Chicago) in the '60s & '70s creating their own "musical world".
Roscoe, Braxton, Henry and Leo Smith all created something really personal and they all continue. We have Muhal to thank for the "atmosphere" and more for these creations.