I think there's a mountain being made out a molehill with his comments.
I'm sure they discuss any number of ideas about speeding up gameplay, and half of them are probably laughed off the table, but they're still discussed. That doesn't mean any of them are going to be implemented immediately either.
Yes,limiting the use of your roster during the game would be stupid imo. That's what it's there for.
I would be in favour of having a limit on how many trips the catcher can make to the pitcher in one inning, and while still allowing expanded rosters in September onward, they should have to declare which 25 are eligible for any given game.
Girardi is probably the worsr offender I can recall making like 3 pitching changes every inning after the 6th, just to play matchups for every hitter because they have 14 relievers available