Consider also that with 4 wildcards per league, you would see more teams in the playoff chase every year and more teams going for it every year as opposed to tanking. So given what has been happening with the free agent market recently, this is something the player's union is clearly going to get behind. I think this proposal has more to do with the upcoming CBA negotiations than with the Astros scandal.
Not only would I watch the heck out of the selection show, but picking your playoff opponent adds strategic depth to the baseball postseason. If you are the #2 seed, do you just automatically pick the #7 seed because they had the worst record? Or do you pick somebody else if, say, the #7 seed is an otherwise bad team that happens to have 2 great SP's and thus not somebody you want to face in a 3-game series.
If you think the single-game WC playoff is an abomination, this proposal jettisons that for 3-game series instead.
The expansion of the wildcard has been an unmitigated success and I think it is natural for Manfred to want to expand it.
I would much rather that Manfred mess with the design of the postseason than mess with actual gameplay. I am not a fan of limiting the number of pitching changes, and one of my great fears is that MLB will implement Manfred's idea of starting extra innings with a runner on second.