It's a teams own fault for being s***. In fact, for poorer teams it could be an incentive to develop better youngsters, plus it would allow these fringe players to improve their game by getting more matches.
What wouldn't change is that only 14 players can be used, but in an injury crisis, these smaller clubs , having given more time to fringe players off the bench, will be able to use players with greater experience.
You keep talking about how fringe players and younger players will get a chance, but if the rule still stands at 3 players max coming on why should that change the managers views of bringing on a younger player or a fringe player for that matter?