It can be done, but that isn't to say it won't take a long time, because it most likely will. Maps have been needing an overhaul since Open Beta. Its been a very long time of hearing people complain about seeing the same scenery throughout entire zones. I understand that multiple textures in the same zones will stress the memory and whatnot, so only other option that I approve of would be to just create multiple zones for each area. It wont be easy and it can't be done in the snap of a finger, that I can understand.