1) Don't trade productive players for draft picks, except as a very last resort. Try to get them back on your team. If they must be traded, get player(s) for them who can contribute. Draft picks just mean more rebuilding.
2) Schobel is not to slow to play OLB in a 3-4.
3) He will probably retire rather than start over at a new position, for a new coaching staff, for a team that is rebuilding (again) but I hope that he doesn't.
4) If he comes back, he will be successful (barring injury) because he is a talented player. In fact, I would worry much less about him making the move to OLB than Maybin. I know that Schobel can rush the QB and make plays because I've seen it. Maybin on the other hand...