What I was curious about was how long the Wildings were allowed to remain unmolested by the Others while they were hanging out north of the wall. The Others/Whites army was already on the move when they attacked the Watch at the Fist of the First Men, only slightly behind the Wilding army at best, marching in parallel with them at worst. The Wildings make it to the wall first, obviously, and they hang out there for quite some time - enough for Stannis' forces to arrive, come to an agreement and bring a ton of people through the gates. What are the Others waiting for? The bunching-up of the Wilding civilians moving through the wall would have been a perfect time to surround and attack a huge contingent of humans that would have been quickly turned to swell their own ranks. The time frame doesn't quite add up to me. Are they aware of Mellisandre's presence and, if so, scared of her? Does her presence and, ergo, the presence of the Red God slow their advance and the influence of He-Who-Should-Not-Be-Named?