While things rarely change on The Big Bang Theory, and even less for the male characters, the addition of Amy to the show has been great. She can be equally annoying as Sheldon, but she has girly qualities which make her seem more human and likable.
"The Isolation Permutation" puts her on full display when she's left out of trying on bridesmaid dresses. She cries, cuddles with Sheldon, and gets drunk outside a liquor store. It's all very funny, yet cute, behavior. At the end of the episode, she gets to be maid of honor, so we actually get a good indication the wedding is coming sooner.