I think that's the main criticism of his swing though. That his hands start forward with his lead shoulder pointed at the pitcher, then as he goes into the leg kick, the hands come pretty far back, the lead shoulder closes off, then everything flies forward and open again. Lots of hand movement throughout the whole process but his timing/bat speed/hand eye get the bat where it needs to be anyways.
The concern is that noisy process won't work against higher level pitching. And really, there's no way to know until he gets there.
But you're right in that it hasn't failed so far, so he's got no reason to make changes.