i'm sure if you wipe it and stay GM you'll get QQers from the enivitable private servers from all those crazed "vanilla was greatest ever forget cataclysm" people.
but i say do it anyways
cause if you don't, you'll end up with poeple who dont clean up their interface folder when 4.0 launhes, install GM2 with curse client thinking it magically emoves GM1 for them, then fill up the ticket system with error reports saying GM2 is broken casue their GM1 is reporting errors.
vs Gm1 staying gathermate1 getting updated and replaced in 4.0 release