As for wrestling, that's sort of apples and oranges...wrestling, although matches are decided by "team" points, is really an individual sport. It only takes two wrestlers of similar nature to provide a good practice that simulates real-match conditions. Not all soccer teams can put together practices that allow players to learn to interact in real-game-style, 11v11 scrimmages...so the only way for them to truly gain that experience is in inter-team match play.
Now you're proposing a system that would make development of weaker players even more unlikely in a lot of situations. So now the ones who, at tryouts in May, don't look like someone I would want to put on the field in every match...shouldn't even be selected? Under the current system, players can be given opportunities as they earn them without posing serious risk to the performance of the team as a whole. A coach in a developmental league does have a split obligation--to the success of training the individual players, and to the success of the performance of the team. Less-experienced players can start off on the roster, train with the rest of the team, and earn their playing time bit by bit as they develop. They can sub in for short intervals to test their development, and have that chance more often when the coach knows he can put the starters back in if it isn't working out yet. I've had players who may have been a liability on the field at the beginning of the season turn into valuable assets by the end. I see no reason to put a coach in the position of having to choose between accepting a weaker player on the team knowing he/she will play every game and may create a weak spot for the team, and denying that same player the opportunity to have a chance at all. As for fitness, for most teams, the key players will be on the field for almost all of the match even with the opportunity to sub. If those players can make it through 85-90 minutes of a match, rest a couple of hours, and step back out to do it again the same day, I'd say fitness is definitely being emphasized. At levels of play where development and competition intersect, playing time should be earned by the athletes, not mandated or restricted by the rule book.
