By keeping Vickery, what are we holding on to. He will never be a superstar. Superstars play well from their first game. Richo, Roughhead, Franklin, they didn't need 100 games to be great.
Versatility? It is very unlikely that he will be a good ruckman, he can't jump and doesn't like physical contact unless he is trying to punch on with a midget.
It's highly unlikely he will be a good forward. He can't take an overhead mark, he doesn't have the work rate and he doesn't have burst speed to get easy leading marks. His hands are like butter.
If in a new club environment, he could correct the majority of those things, (big if), have a huge preseason, at best he will be a good player. He has trade value because he is tall but how much is pretty subjective considering he has a terrible attitude. He has had more opportunities than any reasonable person could expect to prove himself and has been found wanting.
If you could stitch him up in a player trade with another club, there would be very little downside in doing so. I doubt we could get more than a second rounder if we traded him for a pick. Vickery and Shane Edwards for a young KPP would be ideal.