First posts Peeps so be kind.
If the issue is congestion (and making 16 players on the field isn't to peoples liking) and the aim so it make players more tired, why not have a 5 player bench and reduce the amount of bench changes to 48. This way the amount of players on the field spend more time playing and the rest phases for players can be expanded with the 5th player, as their is a 5th player to chop out for key players to rest longer hence (maybe) reducing soft tissue issues.
But obviously with fewer changes, Clubs will have to become much more tactical as to which players will need to be rested. If the issue is soft tissue injuries, then logically, you will want to have your mid-field being the one taking the majority of your changes.
Kind of a happy medium?