In second i think there should be a way of punishing the teams who don't want to compete, the teams that every week use they second team in one game, that teams usually give up of the games against the stronger teams which makes even easier for them win matchs. One example, i'm one of the most strong teams in Portuguese League and there are teams that when play against me give up, don't try to win.
In real life there are no cup games.
And GS.
Well.... Yes and no....
Cup just isn't during the season.... And every 4 years except for qualifiers...
And no game shape but there is fatigue which one could argue is same as stamina... But different players recover their fatigue or from injuries at different rates.
The game shape to me goes back to we need players able to go on hot and cold streaks and it carry over games...