One of the things I have been thinking about for a while is the long-term viability of wood bats.
A number of times this season and in recent seasons I have seen bats splinter with parts just missing players. I recall one earlier this year where a Brewers player (Yelich I think) splintered a bat and missed the pitcher by about a foot. I think it's only a matter of time before a catcher/hitter/umpire gets a splinter in the eye/face or part of a bat into exposed skin.
You didn't see this 30-40 years ago - bats just mostly cracked. Some of that is due to pitchers throwing harder than ever, but 30-40 years ago batters swung hard enough to hit 40-50 HRs per year despite lower velocity from pitchers.
I know from other wood products that the quality of wood is going down. There just isn't enough "old lumber" to meet demand, so trees are rapid-grown and the wood just doesn't get the time to solidify. Then there's the sustainability element. Louisville Slugger goes through 40,000 trees per year making bats. I don't think that is sustainable.
I think that composite bats are in the near future. I'm NOT talking about aluminum, we know that isn't viable. I'm talking about composite materials, think more plastic-like. They use composite materials to make commercial airline fuselages, so they won't splinter. I don't doubt that they could make a composite material with close to the weight/density of wood if they wanted to. Bonus if they could utilize recycled materials.
Obviously rigorous testing would need to show the distance/exit velocity to be within 5% of a wood bat. They can make adjustments to the ball to get closer to the current distance/exit velocity if they want/need to. Obviously they'll need to use them in the lower levels of the minors for a few years first to test in real conditions.
But I think that composite bats, at least in the minors, are within the next 10 years. Unfortunately, I think that something bad is going to need to happen first to accelerate the development.