I wish there was an opt-in page for new sites, which asked for all the stats and connections to the WP servers that WordPress does out of the box. It has always irritated me.
I wish Google Fonts weren’t used in the default yearly themes, as they provide a snapshot of “best practices” and it is difficult to find a theme that doesn’t load Google Fonts. Recently Google Fonts were moved out of core, but that had been one of my sore spots.
I am mostly fine with the user experience, but the server admin and security issues are of great concern, and I don’t like site or servers making calls to third parties without enthusiastic consent.