Other than McPhee (and even then only to a degree, and he was around long before the downtown scene), none of these players really matter to me in any way other than knowing that they're there and that they play well. I'm glad they're there and I'm glad that they're doing that, but..Don Byron? Really?
There's just one too may layer of "detachment" to the whole thing for me...even when it's hot, it's not the type of hot that will burn your skin off, it's the type of hot that makes you look at yo0ur buddies and say "wow, that was hot!" and then go to the bar laughing about, yeah, that was hot!
Of course that's just me, and what is important to me need not be important to you, and vice-versa, I'm just saying...if the downtown scene is important in any "universal" way, then...I'm not in that universe and don't really feel any need to be. To the degree that I still care about such things, I've got other muses to follow. And definitely did when I really did care about such things.
Why is McPhee mentioned among these people?!? Joe has his own thing going that dips way, way back. He was a contemporary of the Ayler brothers and began recording in 1967, and he's still going even stronger today. He wasn't even really playing in the US in the 1980s.
The no wavers were Downtown geographically but had a much, much different thing going on than the improvisers you mention. Sure, some cross pollination with Kip Hanrahan and of course Rudolph Grey's free music trios with Arthur Doyle, Beaver Harris, Rashied Ali, Jim Sauter, Charles Gayle et al. (Blue Humans = proverbial round peg in a square hole no matter the genre), but it's hard for me to think of say, Mars in the same league with Naked City. I don't think deconstruction and concept were as much a part of the no wave thing as some people might like to say. Mars is closer to Albert Ayler than it is Zorn - primal, old-world shit. By the same token, Branca, Chatham, and Russell were composers first and foremost, and made some very interesting and very beautiful music. The first two still do. Arthur Russell's first LP was on Phillip Glass's imprint, Chatham Square, IIRC.