The gameplay problems that both games share i'm referring to are:
1. Sloppily designed boss fights, that gameplay wise have nothing to do with how the rest of the game plays. Poison Ivy bossfight in AA was at least as bad as universally loathed Bryako bossfight in AP. Also, while i didn't mind fixed position camera sessions during the short platformers in The Scarecrow's world using that kind of camera in bossfights was just inexcusable.
Because such fights belong in comic book action games A LOT more than "plausible" and "serious" stealth CRPG games with poor shooter gameplay.
2. You can use stealth throughout most of the game only to discover that in certain situations it's pretty much useless.
Well, an annoyance - but hardly a huge problem, and are you sure some reviews haven't touched on this? I seem to recall some critics mentioning stealth issues in both games.
3. Stealth gets its job done, but could have been implemented much better. You have very few visual and audio clues as to how well hidden you are. Given that the games share an engine i wouldn't be surprised if it was due to the engine. The stealth certainly feels similar aside from AP-s weird crouch animation.
Hmm, very subjective. I thought the stealth aspect was superior in Batman, but the game didn't seem to rely on it to the same extent.
4. Encounter and enemy design in general is weak and encounters get boring fast.
Another subjective thing, that I wouldn't agree with in particular - for either game.
The combat system in Batman is highly entertaining, and though I only got halfway through it, I never really had any kind of issue with repetitive enemies. For AP, that sort of goes with the genre, I think.
Now, these are all serious problems the way i see it. Yet they get mentioned in the reviews for one game and forgotten in the revies of the other. Why?
Maybe because you're reading what you want to read?
Several reviews have touched on the issues I mentioned with AP, and as such I think they're quite fair. Some are too harsh and some are too lenient.
Certainly, Batman is a hype-marketed game - but it was skillfully executed. I don't think it really has any significant downsides, considering what it's trying to do. It's just not my kind of game, overall.
Now, AP COULD be my kind of game - but Obsidian went about making it like they were incompetent. I don't know what went wrong, but something VERY clearly did.