Good point. I, for some reason, am sure that Jo Rowling is planning some thing for Remus. It might not be becoming evil exactly but perhaps coming under the imperius curse, and really needing to be human again. He's often said that he misses being human and with what he says to Tonks, it seems like he thinks that he is below humans as a werewolf. I some how think that Remus will either sacrifice something for being fully human, loss his life or perhaps even surrender himself for someone or another.