And that the only reason for his return was that this just happened to be the moment in time that he was sent forward to when ancient Nord dudes/dudettes used the Elder Scroll? That seems so unbelievably haphazard and random.
Well, he was sent forward in time by an
Elder Scroll. That's pretty heavy in itself. Before now, we didn't even know they could do anything except infallibly record history and show possible futures, while causing their readers to go blind. Having a pro-active affect on the world (under the will of one "wielding" it) came right out of left field. I highly doubt it was a simple matter of "the scroll sent him forward
x number of years." Unbelievably haphazard, random, boring... and therefore wrong.
And what are Alduin's motives in resurrecting the dragons? Some sort of domination/revenge/whatnot? That's never made particularly clear in the MQ...
Paarthurnax says dragons have an instinctive need to rule and dominate. It's something he fights every day, and something even the dragonborn experiences. The stone tablets leading up to High Hrothgar also make it clear that dragons used to rule over mankind before the Dragon War, when Alduin was banished. I think it's pretty clear that Alduin wants to reclaim his position as supreme ruler over dragons and mankind.
1) saving me from being executed by disrupting a kangaroo court and 2) resurrecting his dead buddies, which let's face it, if we could resurrect long-dead friends, who wouldn't do that?
Resurrect long-dead friends, then immediately send them to kill you and terrorize the countryside (I doubt he takes kindly to you re-killing his lieutenants and taking their souls, preventing him from re-resurrecting them). Leveling Helgen, killing all those innocent people (women and children included) who had nothing to do with your execution, wasn't exactly an accident on his part...