My opinion of the like two hours I played of Asylum is a less exaggerated version of this.
I liked the stealth I guess. The cutscenes were nice too. And so was the voice acting.
Rest of the game bored me Especially the fighting and the bosses. It just felt like a way, way souped down 3D Zelda with ok stealth thrown in from time to time and really well directed and put together but ultimately gimmicky and boring villain encounters. Killer Croc was mind numbing, and I remember getting sick of the spammy thug fights FAST. I guess the Asylum was nice looking too but the illusion of openness was created by adding those pointless Riddler collectables. The game was still a linear romp like a 3D Zelda, and I'm not terribly fond of those to begin with.
But I guess my opinion doesn't count much, I just can't get into modern games. That said I watched most of City's cut scenes and every game over screen in the series and I can't help but be glad these games exist nonetheless.