Even though the entire show is based on Disney fairytales, I don't think a new villain should be introduced for the next season. We already have Rumple (who will change), the Author, and now Emma, which should definitely be enough for the first half of the season. I don't see Emma being a "villain" per se but I see her being someone everyone has to "save." I picture season five starting out, like, five months later and we see Emma in another realm (because she didn't disappear to nowhere) destroying things and letting her anger get the best of her. Snow, Charming, Hook, Henry, Regina, and Robin have probably been looking for her for months and then they suddenly find something that leads them to her.
I'm happy with how everyone looked, too: while I can do without Snow's hair, she looked good, and so did Regina. Emma did especially--I find it ironic that a blonde-haired, blue-eyed, white sweater-wearing woman has been turned "dark." But she looked wonderful with it.
I'm ready