I'm seriously tempted to replay it. Or do some of the side stuff. Actually I haven't done the dlc yet, is it worth the cost and is it fun? I'm a sucker for narrative and backstory. Please advise.
The DLC overall is worth it for the price, even of many feel master mode should have been included in the base game.
But even at a pure content standpoint, you will get another Divine Beast, Some more Shrines, a UNIQUE boss fight, some side quests, and a few side items to hunt down through hints that I actually found quite fun.
There is also the trial of the sword, which is very much like Eventide Island but taken to the next level and much longer. You can easily lose 10 to 20 hours in that alone pending on how many times you fail. It is a nice challenge and you unlock the full power Master Sword at all times when you complete all three difficulties.
Lore wise, you get a look into the personalities of the Champions, but it is nothing to write home about. It is fun and offers good content though, so I recommend it if you want some more time in Hyrule.