Plus themes support bloats the GNUstep codebase. I understand that the initial idea was to attract more users/developers, but… It’s not working.
Have you guessed why it's not working?
Users who would be attracted by a different theme are not aware there are different themes or how to set them up.
A solution is to ship a "gnustep-recommended-config" package as a Recommends of the libgnustep-gui package. Speaking in Debian terms; same goes for other OSes.
This package would pull in a theme and a systemwide plist configuring a modernized theme etc.
Today, if a KDE user born in 2001 installs a GNUstep program (they may not care about the rest of the environment), the UI is totally out of sync with their expectations. And if they go through the effort to explore an entire environment, they get greeted by the 90s — whether they want it or not.
Am I misreading expectations of a prospective user?
I mean, these are my expectations, and I'm born in the late 80s. I love e.g. System 7 look. NEXT look is decent to me (but just decent). I'm personally around for the programming language and the frameworks, not for the default theme.
Nextspace seems cool and I should get around to trying it out.