The other main issue is that GNUstep is incredibly bug prone and fragile. Case in point, two years ago i installed GNUstep from source and then built a pixelart editor called PikoPixel. The app felt very clunky, like all GNUstep apps do (note that i'm using Window Maker as my main WM so GNUstep gets the best environment it can hope for). Then two years later with some OS updates in between it doesn't work anymore.

Meanwhile i'm still using the same mediaplayer binary i built ~7 years ago on a different computer against a C GUI library.