As I recall when playing Little League I swung a 30 oz. bat, My son is 10 and I find him swinging an aluminum bat of comparable size that weighs 19 oz. You can get a lot more bat speed with 11 less ounces.
I seen the reports of some deaths attributed (True or false) to this, I've always liked wood and you can't get that sound using metal.
I don't know if banning metal bats is the way to go but as a minimum they should faze in (Say a three year period) such a policy. Some of these things cost hundreds of dollars and I'd be some pi$$ed of if I had doled out that kind of green.
Adding a lead core could solve that "problem".