True, but I don't think we could really insist to a young player who clearly didn't have a future with us that he had to stay because we needed him as third choice. It's that kind of potential stagnation that makes players think twice before joining Chelsea or City, and we'd far more seriously affected given our wage structure. Considering that we probably didn't expect to have both Janssen and Llorente at the club we really had to let him go.
If McGee wanted to go and play, I agree in principle that the club should not stand in his way.
But goalkeepers are in a differnt sitution to outfield players, who may be sufficiently versatile to fill several positions. Vorm has spent some of his prime footballing years as our backup, and Pau Lopez is currently starting for Espanyol having been our number three last season.
It's a tricky one, but keeping McGee for an extra season would not have greatly harmed his career, and potentially would have given us an extra non-homegrown spot for either Lamela or Janssen.