The animations of any 2-handed axe unit mean they rely on a very strong attack to keep any sort of usefulness. If they do the proper charge animation and do not just run into the enemy, then they can have nearly the effect of a cavalry charge. If they don't, they'll get minced nearly as quickly as bogged down cavalry.

Its beatiful when a 2-h charge works though. Even with Mutatawi'a or Woodsmen the whole enemy front line will just disappear.

I used to think they were rubbish because I never made sure they charged properly, but I sorted that when playing as the Danes with their Norse Axemen...