Asylum didn't scare me that much at all... not like Murder House... not did it do a lot for me. And a lot of the storylines just seemed to go nowhere. As stated somewhere else, though, i really did like the last episode, and had no clue what was going to happen until the credits finally rolled and we found out which character was the most hardcore survivor. I guess different strokes and all that.
As a side note, I watched Cropsey today -- it's a great documentary on NetFlix currently about the Cropsey urban legend mixed with the convicted kidnapper (and suspected murderer) Andre Rand over on Staten Island, and a lot of the events centered around the Willowbrook mental hospital there. I didn't realize that Geraldo Rivera as one of his first gigs ever did an expose on that place in the early 70's and blew the story wide open (there was footage of the patients there and it was horrible... basically the asylum had just become a dumping ground, and patients were covered in feces, naked, untended, etc.), contributing deeply to the shutting down of many facilities a decade later.
If Rand actually did kill the missing kids, as he had been an attendant there, it's likely it had an impact on him -- all the missing kids had physical or mental problems, and probably Rand (in his own twisted way) thought he was doing them a justice after what he witnessed in that facility. The documentary really didn't try to "solve" anything, it just presented various facets of the story. (I will say that Rand's definitely a nut himself at this point, you can track his deteriorating/fractured view of reality throughout the documentary by his behavior and letters that are shown. But it's still not clear whether he is truly the murderer or whether he was just a reasonable and convenient scapegoat for the crimes, due to his past history.)
I suspect they modeled Briarcliff on Willowbrook. Even the names are rather similar.