Some people are in FCs that share a different affiliation than their personal GC choice. So people are going to feel inclined to leave their FC and seek one that matches their Grand Company. Do you want them to scrap the GC thing altogether and just make it 3 random teams of 24? That would screw the Lore behind Frontlines up completely. I've never played WoW's PvP but can you party up with an Alliance party leader and fight on the Alliance when you're Horde?