Is ShaderED written by Raven Software? If that's the case then I think it's highly unlikely they'll update it again, being as they've moved onto the Doom3 engine.
Plus it would require them liasing with Ydnar to see what features have been added and that's not going to happen.
Also, the word "project" really does chill me to the bones. Project = work. I'm all for bring ShaderED into our community, but it really would be a LOT of work and I don't i'd be able to contribute anything to it, being as I find programming as dry as bone.
If the source for it was to be released though, i'm fairly sure we'd get plenty of updates from some enterprising coder (perhaps yourself Mr. Vogel). Ydnar could carry on updating q3map2 and whoever is doing the updates could just add them as they come along.
It would be a hell of a lot of work though - demands from angry mappers to fix/update things, knowledge of openGL, video card drivers, whatever programming language.
However, there has to be demand for this to happen. If no-one is bothered about this, then it's not going to happen.
Also, the time constraits - mapping is just a hobby for me and I only get an hour here or there a week to do it. A full project like this wouldn't be fun for me.
It is a VERY good idea though. Ydnar did it for the original q3map compiler. If you can get this project off the ground then i'm sure you'll have nothing but complete support as shaderED works for ALL q3 engined games.