Beat Dragonborn's main questline and I don't think I'll bother with any of the side quests. Solsthiem is a decent size and scope, easily feels on par with Fallout 3's Point Lookout and out of the two DLC's released thus far (Hearthfire simply does not count), Dragonborn is the better of the two but in the end it's still kind of disappointing. At least Dragonborn doesn't feel like a rip off like Dawnguard did (they asked 10$ too much for that DLC) but I'm glad I bought the DLC with TF2 hat money and not my own. Dragoborn is disappointing the same way Skyrim is, it's content tourism not really an rpg. If you dug vanilla Skyrim and aren't burnt out on it, you might like Dragonborn. I'd honestly recommend waiting for a sale to buy this DLC.
The Morrowind fan service is pretty light and superficial, once you push beyond Raveonrock and the surrounding area on the south-west part of Solsthiem it's just more of super barren part of Skyrim. The dungeon elements and most of Solsthiem's landscape are just recycled assets from Skyrim. If you've delved one Draguar filled dungeon or Dwemer ruin in Skyrim, you've pretty much seen most of what Solsthiem has to offer. In that regard Dawnguard and Dragonborn are pretty similar but at least Dragoborn takes place in a new area whereas Dawnguard is just grafted on to Skyrim vanilla. The only real unique elements in Solsthiem are when the player enters the lovecraftian realms of the daedric lord of knowledge but there's only a few jaunts into this realm in the main questline. I guess Dragonborn is pretty similar to Dawnguard in terms of the limited amount of unique locations added as well.
Dragon riding--you gain a new shout pretty late in Dragonborn which allows you to tame and then ride dragons--is awful. You have no direct control over the dragon. You can target an enemy, tell the dragon to attack it and then you just passively sit and watch it wheel around in the air awkwardly and slowly kill the thing you've instructed it to. It would be faster to get off the dragon and hit the enemy with a sword. It feels more like an awkward user made mod than a genuine feature in a studio made game.
The story of the main questline is interesting enough to merit a playthrough but it's more linear (follow the quest markers) unfailable content tourism than an actual rpg, which is a criticism you could essentially level at Skyrim as a whole, I guess.
Like Dawnguard before it, I would recommend waiting for a sale before buying Dragonborn.