Injuries are nit affecting Game, as everyone has a lot of reds. Making red boosters DECREASE (not ELIMINATE) injury time will make the game more realistic, plus other advantages.
1- Make player market more dynamic, as much mánagers play with a short squad. Many of them have only one goalkeeper, for an example. With injuries, managers must have two decent players per position.
2- Make tanking more difficult. As you need 20-22 decent players, at least, you eliminate teams than have 11 players with 6* or more to play cups or associations, and 11 players with 1* to tank the league.
That change will make the game more dynamic and attractive for all players.