Notarisation actually appeared in Mojave, though it was not yet required. I also don't like Apple having to validate every app I run. Sure it adds security but in this case it depends on the decisions of hundred-billion-dollar company. Whose interests are probably not 100% aligned with my own. I miss the ability to override things when I deem it necessary.

Hello desktop looks good indeed, though a but too early for me too. Right now I use KDE on FreeBSD. It's a bit too 'Windowsy' but Gnome is far too much 'new Apple', taking away user choice, so it's not an option for me.