TV Tropes, Face/Heel Turns, and Loki

I still haven't been on here much because I got sucked into Marvel Movie Universe by Thor and The Avengers. That and TV Tropes. The last one alone is quite the time drain. Combining the two has landed me with The Sorting Algorith of FaceHeel Turning and me figuring out where Loki fit on it. In other words, how likely was it that he'd turn traitor in Thor and how likely is he to be redeemed in some future movie? Oh, and potential spoilers ahoy under the cut. ( Long post is long. )