Why would giving 48 minutes to the players of the winning team in a walkover (if they are set at all three spots in their position) be a bad thing? Give me one reason it would not be better than 43 minutes.
There is no free minutes. Every second of time for training is connected to risk of injury and difficulty of player time management. There you go.:)
Thats exactly my problem when they just remove the penalty for starter backup, then you will have scrimmages with "friends" who just forgot to make the lineup(especially during the PO, when they are out and training ft/stamina), but i could also understand the anger of some managers with this system especially because it isn't communicated outside of the forums.(maybe they need to put the minutes rules into the rules)
Another solution, and the solution i like to see, that they use a standard bot team to play against to consider the minutes and injurys after it you could make the result 25:0 and give the forfeited team a star.