In August of 1975, I remember watching (on TV) Spacemen Bill Lee throw a complete game in slightly under 2 hours...the great Bob Gibson didn't feck-around on the mound either...
If MLB is truly serious about quickening the pace (a 9-inning game being longer than a football game is a Disgrace), then it should, at the Bare Minimum, limit the # of pitchers on a 25-man roster to a Maximum of 12 (20 for the September 40-man)...then it should very seriously consider limiting the # of pitchers used during one game, or even during one inning...Pitching changes are By Far the worst culprits for this awful, unwatchable time suck.