Easy answer is to add more training, So players develop faster, there already components in the game that balance the added training game shape , stamina , minutes.
3 training a week.
1. One on one development in gym(rookie player or newly bought player).. "Does not have to be in starting line up to train." 1-2 season time. KInd of like in soccer/futbol where they develop a player on the side
2. Team tactical training( new offensive/defensive training coaches)
3. Bb style of regular training, with a new twist of to *be able to select training minutes directly, given in the stamina and fatigue*
Since trainers are kind of expensive at times and worth goes up over time, these thing make it worth the effort. It keep managers logging in and trying new things or styles of play.
Training player to a style is already in the game, its needs to be more open in development. Random pop and all that will be the same