Ben won't welcome Kerwin Walton back, unless there is evidence he can play much differently than he has last year or this year. Yes, he shot the ball well last year, but he does not play real good defense, does not handle the ball well, and has a lot of turnovers this year. That's why he's not playing - defense, and contributing anything other than shooting.
Ben Johnson has made very clear the type of players he wants, and he is unlikely to welcome any players, native Minnesotan's or others, who are one-dimensional. People get so hung up on positions, labeling players as a center, forward, guard, etc. If you listen to Ben, and watch how guys are playing this year, he does not care about positions. He wants players who can play off the ball, with the ball, and on the perimeter. And, he wants them to be able to guard multiple as well. He will likely play one big who can guard, but will want four players who are can play on the perimeter, not labeled as a 1, 2, 3, etc.
All that said, Kerwin Walton, unless he commits to being more than a shooter and playing differently on defense, does not fit that type of player. And, if he demonstrates a willingness to do that he'll likely get playing time at UNC again and won't be transferring.