In the era of Flatpak, I kind of agree with you.
The primary drawback is the complete lack of packages. A home user is going to want something not included and then things fall apart. Flatpaks and Distrobox have made that a lot better.
If you could get away with a RHEL core and Flatpak for apps, you would have a pretty solid setup for a “normal” person.
The release notes refer to the “few remaining issues”.
https://gitlab.gnome.org/GNOME/gimp/-/milestones/3#tab-issues
There seem to be 115 issues on there which is more than “a few”. However, only 3 are listed as blockers. But a dozen of them are crashes.
How many of these need to be fixed before the 3.0 release? Does anybody know?