I'm not sure why neck training isn't more common around crossfit. Having a strong neck is at least as 'functional' as most anything else that's done around here, and is very important from a safety standpoint. Training for the 'unknown and unknowable' (or whatever the saying is) should at least prepare you to take a shot to the head, be that from a foot, fist or something falling from a high shelf, etc.
Coming from a football/wrestling/rugby background, I've always trained my neck. It doesn't take a lot of time or energy, and you get a lot of reward for relatively little effort.