Arkham games (not counting the WB:M one) are all great but the first started out with a great setting, good writing and good and fun combat.
Arkham City made the combat better and more fluid but everything else got worse.
Arkham Knight made the combat better and more fluid but everything else got worse.
They just got too hung up on gadgets and side stuff. Arkham Knight is also the best case I've seen not to listen to fans. From the moment AA came out people wanted the Batmobile and I'm 99% sure the people making the games said "Nah, doesn't work in this type of games" and ofcourse most of the fans (at least on GAF) hated it. The side stuff should've been one offs, Like "Hey, Two-Face is robbing this bank, go get him" and after that its over, you get Two-Face. Not having him be at 3-4 banks.