I restarted my game recently and have been putting off the main story. Do you think we will need the main questline to be finished in order to start the Dragonborn DLC? I'm assuming so, seeing as beating Alduin.. well the next best thing would be the first Dragonborn.
I don't see how it would make sense while in the middle of the main questline you just sort of " Oh, I'm going to travel to Solsthiem and kill the first Dragonborn real quick... NOW, BACK TO ALDUINN!! "
And also, what do you think the level requirement will be?