I did raise my destruction skill up ~20 points (thanks for that) by zapping him with a lightning bolt every time he flew by (well, every time he flew by close enough for an attempt, and every attempt I actually managed to aim well enough to hit him). Yes, the dragon clearly knew where I was, as he was turning his head to track my stationary position the entire fight. Yes, I was "in combat" with him the entire time - his slowly dwindling health bar was on my screen and his red dot was on my compass. And I'm pretty sure I heard every epic dragon fighting score in the game several times over, enough to get sick of them.
But the dragon simply would not land. Or hover. Or shout his dragon breath weapon. Or attack in any way. He just wanted to fly around my position on wide open terrain endlessly. The sun set, rose, set again, rose, set again, rose, and finally after setting one last time I managed to force him out of the sky, at which point I walked closer (I was encumbered.. a big thank you to the dragon for skidding to a stop 100 yards away and sitting there, making me walk over to him instead; really appreciated that final inconvenience) and put him down and us both out of our misery with many arrows.
We are now at patch 1.3(?) on the PC and this bug (which is nowhere near as "rare" as Bethesda likes to claim it is) is still not fixed, despite the patch notes insisting it is. Please fix it for real. If dragons are going to be the star opponents of your game, you should really make sure they work.