I really don't see Trimble leaving, he gets playing time, he has a specific role on the team, Groce believes in him, to my knowledge. I think Wynn leaving is a real possibility, he doesn't have a set role, he doesn't get along with the coach, and I don't think any starters will leave a spot open for him.
One other guy I could see leaving would be Mikal Dawson; he's going to be a "junior" (4th season) still not having a starting spot (that I can see). His sister is going to be graduating, not that would be a huge factor, but it could make it easier for him to leave. I really hope he doesn't transfer, but if he continues in this 6th man role next year when he is capable of starting, I could see him on a different team next year.