The electronic strike zone (I admit I'm a purist and don't like it anyway) will only add to the game length problem. You think MLB umpires miss balls and strikes today, go back and watch these games from the 70s and 80s. If anything umpires have to be too tight with the zone today. The zone was much bigger in previous decades and good pitchers could "earn" pitches and expand the zone. It's a huge part of the game. The modern zone (actual, not rulebook) is so tight it wears pitchers out, leading to an average of around 9 pitchers per game. That's what adds time to games. That and more balls being called and batters taking a lot of pitches.
It's really clear when you look at the averages from the 1950s through 80s. Games were around 2:30 hours long and averaged fewer than 5 pitchers per game. Now game times are over 3 hours and average 9 pitchers per game. That's ridiculous. Using the electronic zone (which is so much smaller than the effective zone has been for the rest of the history of baseball) drags the game on. It also makes the game more boring to watch. Lots of taken pitches, less swinging.
Talk to any pitcher and he will say the same thing. Pitchers, catchers, batters, umpires, all working together to establish a balance is the centerpiece of the game. Pitchers have to be able to earn strikes and expand the zone. It's part of the competitive balance. Otherwise we can just put the ball on a tee and let weightlifters try and hit the ball 600 feet every time.
And on a related note, in the past when umpires called a wider zone, it didn't destroy the offensive side of the game. The total runs per game in the 60s-80s is within a run of what it is now. Batters were just better at batting and not weightlifters looking for the ball in a solo cup-sized zone to tee off on.