When this happened in the 60s the solution was to lower the mound, which actually has a pretty big impact. It does slightly change the way pitchers have to throw, but to me that would be the easier solution, but we may have already reached a limit where the mound is as low as it really can go (I guess they could make the field flat, but honestly that changes alot of things, including fielding up the middle, etc.).
I think they need to avoid messing with the mound until it gets extreme.
Hitting and Pitching fads come and go based on how teams win. In the 80s suddenly (due to KC) there was a slap hitter, ultra speed craze for years that honestly made the game more exciting in alot of ways, but HRs werent the "thing". Now it is all HRs and strikeouts, but I suspect this will change if a team wins another way (yes, I know there are analytics pointing this way, but some team gets 2-3 base stealers that can get on base and win a WS and watch how fast the league changes again).
OBP will be back, slap hitting will be back (I suspect), it just isnt in vogue right now.
Speeding up the game is easy, pitch clock does it. Right now the breaks between pitches is just way, way too long when you are going to need 350 pitches in a game. Years ago when it was 250 pitches it wasnt as big a problem.