The fourth season of MTV's "Teen Wolf" premiered tonight.Crystal Reed is no longer a series regular after her character Allison Argent was killed off in the penultimate episode of season three.Loved cold open with Stiles and Lydia walking through a Mexican town bickering about the lethal stupidity of their current plan. When this show finally ends, I'd love a spinoff featuring Stiles and Lydia as paranormal investigators, because their dynamic is wonderful.I think the fact that Kira was in retrospect so obviously introduced as a replacement for Allison, it's sort of hard to accept her as part of the group because she's not Allison.On the other hand, the introduction of Malia as the pack's new B. A. Baracus was a pleasant surprise. Because her thought process is still driven by spending more than half her life as a coyote, her perspective is completely unlike any of the other characters.The premiere also marked a big expansion in the show's scope, with a couple sequences worthy of an Indiana Jones movie. It sort of drove home the importance of Beacon Hills to the show, because the absence of the show's excellent cast of supporting adult characters was keenly felt. And the mythology continues to grow ever more convoluted. On one hand, I like that they ground it with bits and pieces from real international mythology, it gets more difficult to keep track of.I like that Lydia's banshee powers operate completely different than the aggressive physical powers of the other supernatural characters. I hope we get more insight into how banshees work this season.