In training menu we must click on every player and select his subtitution.

I think will be better fo us to drag and drop players. Players to switch possitions faster and another problem will be solved:

(now when you make a substitution from the bench , you take the player from the bench and insert him in the field, but the place from the bench remain empty,  the player from the field is not taking bench possition)

PS: Please remove/lower the cooldown from upgrade statium facilities. At this moment is just a way to stop players to invest faster in the team. We all want progression in this game.

just invest first on your training centre, after that the other ones. I dont see the really problem, so long you have your priority on good way.