gbryant I should probably ask, how exactly are the those themes "broken"? I keep hearing "broken", but I've never seen a broken theme before. Some GTK applications don't integrate well with dark themes, resulting with text or icons that are hard to see, but as you stated, GNOME does have Adwaita Dark, so this shouldn't be a problem.
As for accessibility, there's also a matter of fonts and size. This can be also solved with scaling, but again I had problems with it on GTK apps before and being able to change fonts gives more freedom.
I don't really care for GNOME, so it's not issue for me personally, but I just can't see why GNOME people are so set on not having themes in the first place, when pretty much all toolkits for GUI support them.
And when distro maintainers hack it in their own, they get mad. Linux is all about hacking. FOSS is as great as it is because I can take someones else project, edit parts I don't like and redistribute it. Original creator shouldn't care. If they like the changes, they can integrate them, we can work together. If they don't, they should just keep doing their thing.
Hell, if GNOME added theming, distro maintainers wouldn't have to "hack" anything. They'd just add their own default theme, leaving GNOME one for people to use if they like it better.