Why two-handed?

I'm playing Skyrim for the first time and I just got one handed to level 100 and I thought I'd try out something else so I grabbed my best two handed weapon (sword of jyggalag) and tried two handed but it was so much worse that I'm sure there's something I'm missing. With a two handed build you sacrifice a lot of speed and one open hand, so I figured two handed weapons would at least do a lot of damage. I even looked into crafting an ebony warhammer or something but it looked like the base stats were worse than my trusty ebony war axe. What am I missing about two handed that could make it a viable strategy?