Exactly that. I can essentially add/remove drives on a whim (for any reasonable definition of "on a whim") using btrfs and run a rebalance command afterward an

Exactly that. I can essentially add/remove drives on a whim (for any reasonable definition of "on a whim") using btrfs and run a rebalance command afterward and I'm done. That, of course, is really not a concern for enterprise use cases.