Well that's got me thinking... The "Army of the Dead" in the show looked a decent size in season 6. Having said that, though, I can't see them being very tactical. The shield wall used by the Bolton Army might be effective. I wonder why they're so few "Others" then? My first thought was that perhaps only certain people can actually be converted? I was going to say King's Blood but we've seen Craster's son being turned in the show, and he certainly was not a King. Unless he can trace his descent to a King-beyond-the-Wall?
I really hope the Humans vs. The Others isn't a traditional battle such as one of these pitch field battles like outside of Winterfell or when the Wildlings attack the wall. What are the humans even going to do? Use flaming arrows all? Are Lord Beric and Thoros of Myr going to show up and hold a seminar on how to set your sword ablaze? Even with that said, the Northerners and the NW don't have enough obsidian and they don't have valyrian steel. Most who show up at the Wall will flee when the Others show up. What's the point in standing there with no way to kill your enemy and just resigning yourself to death?