Board Thread:Skyrim/@comment-11276487-20130706234318/@comment-6881629-20130805162645

Or as Paathurnax and Arngeir say, Alduins soul was saved by Akatosh so when the end of time comes natually Alduin will then be alowed to return and fulfill his prophecy as the World Eater.

I don't think he was underused. He appears and destroys Helgen he also appears at every Dragon burial mound (if you time it right) not just the one in the main quest and on top of that you have to fight him twice. Dagoth Ur you only get to see once.