This is the reason Alexandria people are so unskilled with the walkers. They said in an earlier episode that the area was evacuated, among the first to be during the outbreak. They were pulled back in by the military. Because of this, people died elsewhere so there were few, if any, walkers in the area they were in during the beginning of Alexandria. That's how they managed to keep all the homes in tact and construct the walls as well. They've since been living inside, so have no combat experience with the walkers.
Definitely thought this was a much better episode. I was sad about Noah and felt his character was a waste. He didn't contribute much to the show, it would have been the same without him. There was some speculation that his character would tie in with the return of Morgan somehow, because when Noah was introduced he told Beth that he had come to Atlanta to search for his uncle and cousin (read: Morgan and his late son). I suppose that connection is still a possibility, but has much less of an impact with Noah now being dead.
I was glad to hear I think Rick say in the previews "they don't know what they're doing" - presumably about the Alexandria people. The guy with Abraham and the guys with Glenn had the same abandon mentality because they don't know what they're doing.
Speaking of the guy with Abraham, does anyone think he has a hidden agenda we haven't seen yet? What would be the purpose of him going to Deanna and telling her that Abraham is better than him? He could just be genuine, but that's rare in that world.