Just finished Arkham Knight. The gameplay was tight, and it was interesting to see how Rocksteady expanded and improved the stealth and combat between each game.
It has my favourite story out of the trilogy. There was a lot more going on internally with Batman, and the Joker hallucinations were piff. The Arkham Knight was kind of a whiny villain, but he still served the themes of the story along with Scarecrow.
I think it has the weakest level design out of the trilogy, can't think of too many spaces in the game which were interesting to navigate through (Stagg airships, Arkham Knight HQ, and Ace Chemicals if I'm being generous). Despite being open world, at least Arkham City still had the museum, steel factory, subway, and Wonder City.
The Batmobile was cool outside of the tank stuff. I enjoyed racing and using it to solve puzzles like any other gadget.
Can't wait to see what Rocksteady does next. The character switching mechanics in Arkham Knight feel like they were laying the foundations for the rumoured Justice League game.