I wouldn't mind if the DS went 7 games instead of 5 to be honest. It's only an extra 2 games which I'm sure they could squeeze into the schedule. Plus means extra $ for owners and baseball.
I remember the NBA went with Best of 5 in R1 before but then changed it. NHL makes every round Best of 7. Don't see why the MLB can't have three rounds that are best of 7, when the other leagues have 4.
I said this before but I think having a full 5 days off or even more for the top teams doesn't help them. Baseball is a game of routines and timing for players and playing everyday consistently is important. A 5 day layoff likely does impact some players or pitchers. I know some have said well those teams could still change their workout routines, play simulated games, etc., but it's still not the same. I would suggest having the WC matchups right away after the season is complete like play the Monday, Tuesday and Wednesday, and then start the DS on Thursday or Friday. Instead of two days off, only give the WC teams one day off either before or after their WC series.
I understand the issue with tightening the schedule in the Postseason could be an issue if weather doesn't corporate. You do keep an extra day after the WC at least if one of the games is rained out. Doubt they would allow a doubleheader to be played in the Postseason haha.
DS should be 7 games though. I think that would definitely be a start, even if it means the Postseason finishing a couple days later. I'm sure MLB could make it work without shortening the regular season.