Only down side to waiting too long to start the MQ is that the guards who help you kill the first dragon have a lot better chance of surviving the fight with a low level dragon. I try and start the Main Quest around Level 5 but I've done it as low as level 1.
I typically stop right around the time they send you to see the Greybeards so I can kill dragons. I finish the rest of it later.
And whomever mentioned the staves, that could work. Would shooting Illusion spells at it eventually cause it to land? I know not getting into combat and trying to evade them makes them give up, but if I'm shooting stuff at him, even non threatening crap you'd think would be a flag to go HEY COME EAT MY FACE MY AXE WANTS TO SAY HI.