Regarding #2, I think the biggest plus is that it will be slightly safer for the pitcher. On the other hand, giving the batter a bit longer to size up the pitch may mean more line drives up the middle. It's hard to know, which of course is exactly why experiments are performed. I think this will be a much bigger adjustment for the pitchers than the batters and catchers. (I was going to include umpires but then I remembered #1.)