Probably not, I see what you mean but no, it should be a crisis and you have to face it no running away, stand and fight !
bliviongate:
Every crisis has to start somewhere. The crisis doesn't have to be present from the very beginning of the game.
And the Elder Scrolls is supposed to be about freedom, it's about doing what you want, trying to force a certain path on the player is contrary to that point.
I thought It looked at how long since you encounted a Dragon and other such things to trigger an attack....?
It sounded to me more like Radiant Story looks at how long it's been since you've fought a dragon to determine if it should give you a quest which will require fighting a dragon or not, but random dragon encounters can happen any time independent of Radiant Story.
But at this point, I really don't know how this sort of thing is handled, but the way Bethesda has talked about it, get the impression that dragons are present in the world from the start, no matter what you do, although I'd rather they only appear after some point in the main quest, so that if I don't want anything to do with dragons, I can avoid them. Now, even if they're present from the start, you can always run away when you see them, of course, but even so, if I can see them at all, it will serve as a constant reminder that there are dragons, and could potentially create a situation similar to Oblivion's main quest where even though I know that the gameplay will let me ignore it, it feels like I'm neglecting my own responsibilities to do so. Especially when you consider that dragons can attack towns, I'm sure that Bethesda has a way to prevent important NPCs from dying because a dragon attacked when you weren't around to do anything about it, but minor characters probably don't get the same luxury, and it's not going to feel right if towns keep getting depopulated of all random characters because I didn't want to do the main quest with my current character.