There HAS to be something that can be done to improve substitutions - minutes played. Like assigning each player target minutes per game (0-5, 5-10, 10-15, etc.). I was called a "lazy" manager in the new Season 30 update for using blank lineups, but the truth is I didn't like using blank lineups. The only reason I did is because the amount of minutes starters play in the game is horrendous. Even my mediocre stamina PG played 40 minutes last night. Now I have to bench my two best players EVERY OTHER GAME just to keep their game shape up.
If there is not going to be anything done about this I have another suggestion. Any manager at any time is allowed to reduce the stamina for any player on his team for free. JUST reduce, not increase. For example, if I have a player that has Proficient stamina I can permanently reduce it to mediocre or inept, but once it is reduced the only way I can increase that players stamina is thru training. Sometimes you find the "perfect" player on the transfer list, but his stamina is prominent, proficient, or strong (a bad thing ONLY in buzzerbeater), and you know you will never get the most out of that player because either A: you play him every game and he's only half as productive as he should be because of sub-par game shape, B: you play him every other game to keep game shape high, or C: bring him off the bench. None of these are realistic options.
This is a great game and sure there are many small things that can be improved here and there, but to me this is a GLARING weakness of the game.