What you raise regarding minutes affecting form is true, and previously I have suggested that the BB powers can manipulate in the finals the affect of minutes on form, as they currently manipulate the affects of effort level in the finals.
Despite that you answered your own question, it would mean sitting some of your players out, or start them on the bench, in effect managing your line up as you go through the finals to make sure you get the best out of your team. Not eveyone will agree with this approach, but I would find it a greater management challenge, and therefore of greater interest, during the final series. In my league the team that knocked me out in the semi finals completely changed his back court in the first game of the finals, relying on his tactics in order to rest his regular starters, making sure they were fresh for the 2nd game. He still won the 1st game of the final series. This is an example of what I believe is the great thing about this game, managing your team.
And before I get some of the responses I have received previously wheh I dared to mention my own personal views...SO....., who cares what you think. I added the last bit :P