I guess they could always add a fourth faction, which is basically just a group of mercenaries that can fill any slot in Frontlines. Leaves the Grand Company aspect in place, but allows people who don't care for it to queue with friends/etc... Though I guess the reason people cannot queue with friends already is because people don't want to leave X Grand Company, so maybe not... Is that mostly down to glamours? They could always let the fourth faction purchase and equip from any Grand Company, but perhaps at an extra cost.