The issue isn't that shotgunners would hate it. It's that every fanboy has a sniper rifle. The undeserved glamour and mystique of these weapons means every twelve year old secretly fancies themselves some kind of elite sniper. They jump at every opportunity to 'prove' this (generally by losing control games). So big, open maps can't exist. Everyone will just spam snipers and wreck the pace of the game. Which is a shame because the movement, radar, vehicles and weapons all seem designed with large maps in mind. If snipers were a heavy on the other hand...