I am not one of those folks that feels the game takes to long or is losing fans; but baseball players and strategies have changed and the game needs to adjust to this to keep it interesting.
I start with the premise that baseball is most interesting when there are the most balls in play and teams have an opportunity to produce come from behind victories. In 1987 28% of plate appearances ended in strike outs, hit by pitch, walk or homerun. In 2016 34% of plate appearances ended in these. That is 6% less baseball happening. Homeruns are still around 1% of this. In order to make baseball more interesting, baseball needs fewer strikeouts and walks and more likelihood for late inning scoring. So here is what we do:
1. Players are bigger. Pitchers are bigger and can throw harder (on average). Batters, with greater raw power, hit more homeruns per balls in play(on average). Taking these facts into account two adjustments can be made which will lead to more balls in play: Lower the mound by two inches and/or move the rubber back by five inches. Either one will decrease the affect of pitchers being inches taller than they used to be.
But this may cause them to walk more folks unless other adjustments are made. The other adjustment is to widen the plate by 1.5 inches and stretch the strike zone to include the high strike (this is supposed to be done this year anyways.) Batters will have to cover more of the plate and as such will be less able to swing for the fences. They will have more time to react with the changes to the mound; but will have to be hitters not just sluggers.
Basically what we have done here is increase the likelihood of small ball and players covering the plate by taking a hittable ball on the outside corner the other way. This should decrease shifts as more players will use the whole field.
2. Current Strategies limit opportunity for success late in games: Correct this by limiting the number of pitching changes to one per inning and stop catchers from going out to the mound after the batter has begun his at bat. This forces a Manager to leave a struggling reliever in the game and reduces the opportunity to play the match up game as much. Managers may be more likely to leave a pitcher in to start the next inning than make a change at the beginning. And if catchers can't get things straight with signals than they just have to deal with the results.
There are other potential ideas including stopping shifts, limiting the number of relief pitchers after the seventh inning, widening the diamond to provide more fair territory, or widening the barrel of the bat that are options that could be explored; but I feel the options presented here would upset the fewest traditionalists. Is baseball willing to adjust before half of all at bats end in strike outs, HBP, walks or homeruns? Lets be more interested in making baseball more interesting rather than shorter.