Stupid Winterfell defence
Why not post meagre amounts of archers along the walls, instead of trebling the amount at least?
Station your brilliant skirmish cavalry in front of everyone for an insane dash into the darkness (even with the unexpected fire swords)
Everyone (almost) stand before the catapults and castle walls, instead of inside to defend against a mass foe of charging undead?
Why not just set one, maybe two lines of trenches against this deadly foe? Durr, Caesar in 52bc at Alesia set several trench-traps etc and that was against Gauls, not undead wights?