This awkward feeling when you feel more involved in a DLC than in the game you actually spent many hours on. I totally understand why this happens: The Witcher 3 is a huge game with multiple side quests and characters - and while playing it I sometimes felt bored with some lines. In the DLC you don't have so many side activities - instead there is a tense action, a great story, awesome characters and, in fact, just one location - Toussaint - that looks stunning.
Do you have the same "problems" if to say so, with other games?
I heard that BioShock's "‎Minerva's Den" is outstanding, and Borderlands' ones too.