I was thinking that It would be cool if Winterhold was rebuilt.
This might conflict with already existing quests but there may be a way around it.
To be rebuilt, maybe the player could convince the mages of the college to come together and raise the land from the sea.

Would this be possible or worth it?

My guess is Thalmor based major DLC will be released first. The Thalmor are pretty thick in the behind the scenes of the game, it's almost a certainty that there is a major plot being built up behind it.

Yeah, the thalmor will definately get the 1st dlc I guess.