Trophies were a fun diversion without complaints. But about the Challenge rooms:
I completed AA challenge rooms 100% and still continued to play them for dozens of hours. But as AC hit I just couldn't ignore the sense the repetition and lack of innovation and I didn't even bother getting 100% in it. Every challenge has you beat up the same 4 waves of enemies or clean up a room silently, in areas that I've seen in story mode.
But. I loved playing as Robin and Nightwing. So I feel that is where next Challenge mode needs to strike - Forget all about Batman, whose gameplay we have seen to the death. Instead change up the gameplay by making Challenges focus on everyone else. Allow us to choose pretty much any hero or villain (Joker, Harley, Penguin, Two-Face, Bane, Poison Ivy, Gordon, Batgirl, Zsasz, Ra's, Clayface...) and beat up a group of thugs or clean a room. Additionally make us play as Penguin who invades Joker's turf and uses his umbrella to complete his objective. Or make us play as Clayface whose goal is to escape Arkham by using disguises...
And co-op challenges too. Batman & Robin specific co-op or competitive challenges would be awesome. As would Two Face vs Penguin turf war. Or Bane & Killer Croc working together against thugs or competing who kills the most thugs. All the stuff that you don't remotely see or do in story mode.
Now someone says that they rather focus on good story mode instead of challenges, and so would I. But AC has lots of samey repetive challenges. I wouldn't mind if Arkham 3 only had about 5-10 challenges and maps as long as they're unique and completely different from what story mode offers.
1. Combat survival - "Pick any character and defeat as many thugs as you can"
2. Predator survival
3. Co-op Combat - "Work together to take down the thugs"
4. Co-op Predator
5. Competitive Combat - "Who defeats the most thugs and gets highest score"
6. Competitive Predator
7. A handful of character specific challenges - "Sneak your way away from Arkham as Clayface", "Infiltrate Joker's hideout and steal information as Penguin", "Stop the rioters burning down the park as Poison Ivy", "Defend your turf while taking over Penguin's turf as Two-Face", "Protect Nora from attackers as Mr Freeze", "Steal as much valuables you can before time runs out as Catwoman" etc.
Being able to play as a dozen characters and in multiplayer would truly set Challenge rooms apart from the story and breathe new life into it.