This might be quite irrelevant to the topic of libAdwaita, but I this page very nicely lists out all the awfulness of GNOME beautifully. That's why GTK-based desktops like Cinnamon (my daily driver), XFCE and MATE exist. I would request the devs to have a look:
https://woltman.com/gnome-bad/
GNOME tries to be the "brave guy" and discourage the use of the "traditional" desktop layouts like Windows or Mac, but, is it really practical? Some GNOME users go "Oh it removes clutter from your desktop... the taskbar approach is distracting" You can get the same experience on any of the other GTK desktops by:
Right click on Panel > Panel Settings > Auto Hide Panel
And it's much more usable, because you can change between different instances of a program very easily from the panel. (Many (most?) GNOME users install Dash to Panel / Dash to Dock anyway.)
And the huge buttons and spacing in apps, oh my. Disaster for screen space.
Promoting libAdwaita is kind of making GNOME the Linux giant (which it will never be unless KDE dies somehow). It's just reducing choice for the user. Why not use plain GTK4 when it works fine on all desktops?
P.S. I'm not really sure if work on libAdwaita has already started. If it has, I guess we'll have to roll with it.