One thing i like in this game is that every player, even the best ones, sometimes performe clearly below their average quality and other times better than they usually do. It's plesantly unpredictbul and realistic.
So i think coach's decisions system should also be somewhat more flexible and have in account the performances of both starter and sub in that particular game.
About multiple substitutions and weird timings such as 1 or 2 minutes in game, or entering in the end of the quarter to get out before the next begins... Don't you think is a little too common?!