Alduin with deadly dragons on hardcoe is one of the hardest things to kill in gaming. But I agree that Harkon had more effects and it was done better, still too easy, but I don't complain about bethesda's easy bosses since Dagoth Ur.
Agreed, on both counts. I remember back when his health was about 10 times more than it should have been... Was entertaining to say the least. In a future update to DD, Alduin will have the same damage as a Legendary Dragon, but with about 30% more health.. He'll also be a static creature and not scale with player level.
Back to topic. I haven't actually completed either questline yet (dragging the DLC out as far as possible), but I've watched a video and the Harkon fight was much better mechanics wise than Alduin, who was just a generic dragon with both breath types & a weather effect shout. The setting & build-up for Alduin was better in my opinon.. The actual fight itself svcked.