It does not take the entire alliance team to turtle the bridge. But apparently modern alliance cannot do more than deathball. And how can I forget that despite having the bulk of horde trying to get across the bridge, there are also 40 horde at IWB, 40 at SFGY, 40 at IBGY, and a constant stream of 40 issuing from the cave (that is “right next to IBGY”). (oh, and 40 guarding the “secret valley” where Lok is summoned)
No wonder alliance cannot obtain any objectives, what with a full 40 man raid at each tower, GY, LT, and god summon.