I'll tell you why I'm thinking along those lines... back in the summer Soap Net did a "Reveals" show where they told the audience what was coming. In some of their reveals they were kinda hints more than reveals but in others they just came out with it.
One of those reveals was that Bo and Nora would be getting back together. Now they've got Nora engaged to Colson and if they're going to put the two of them back together, which I think they should anyway, they've got to get rid of Colson. That would wrap up two storylines and open a new one all with one stone.
Plus they've had Colson's behavior change a bit. Bo's commented he's not so sure Colson is one of the good guys. He's also not one of the main characters so he could go to jail without it disrupting the rest of the cast.