> Just the fact that people need a ton of shell extensions to make it barely usable is a problem in itself

Other than 'native window placement' I find that pretty much every extension I have installed is a customisation where I want something to work in a particular way. It's not that Gnome is unusable by default, it's just more the minimal set of features that everyone uses.

For example, including a time tracker on the top bar by default would be wasteful, as would a timer. I want both of these though, so I go to a website and click a button and they work.

However, the lack of proper sandboxing / permissions breakthrough for the extensions is a real problem I don't believe has been solved yet.