The Gimp project has been quite abrasive to the graphics research and software development communities for many years. The Gimp team 'knows better' then the highly qualified and experienced graphics programmers who offered to help the project bring there code base into the current standards for graphics.
There has been a lot of goodwill that has been squandered by the Gimp developers to the point that I seriously doubt that anyone with the skills or the time to work on OSS graphics is willing to invest any time in the project.
Any further development of Gimp will more then likely be an upgrade to the latest version of the GTK+ toolkit slapped on top of the same outdated 8bit early 1990's architecture fallowed by praise by people who have little experience or interest in graphics at any serious level.