I hate it. While I don't like having to sit through 4 pitching changes in an inning, I also don't like the idea of telling a coach he can't bring in a guy because the dude on the mound hasn't faced enough batters. Also, I find the "3 batter" minimum to be such an arbitrary number, why not just say a guy has to complete the inning he starts, no pitching changes outside of injury.