I think I’m in agreement to pretty much all of these.
I’m not sure about the technicalities of date updated, though. Currently the theme list is pulled from a single location, and when you apply the theme, it goes and fetches the data from that theme’s github repo. To get the date updated, the plugin would have to ping the repos of each theme individually to get the data for the last commit (you’d probably specifically want the last commit that touched obsidian.css).
Alternately, one could potentially make a script that goes and gets those commit times and updates the main metadata once per day or something
but that would require something outside of Obsidian. Not impossible, though.
An update button is also potentially tricky in that Obsidian will have to keep track of when the theme was last updated, and possibly also if you’ve made your own changes to obsidian.css as well (as any changes would get wiped when the theme updates). Though I guess that would be covered with the current warning you get when you apply a theme…