That's what I encounter when I contact managers for U21 players. The situation you describe happens too I believe, but I think if the concept of training (it's more effective for younger players) is clear, that problem will partially be solved too. I do believe some managers will be confused by the term potential, and think it's more than it is, but I don't think a change in the name is necessary because it's accurate. Some additional explenation might be good though, to make clear it's just that, potential and without work it's worth nothing (like in real life).