Isn't it funny then that BTRFS supports growing and shrinking? Sounds like it's not such an edge case at all. BTRFS is also focussed on the enterprise, yet it is implemented.
People have been working around the limitations of lvm and Linux raid for years... it's not such a big deal. The issue with BTRFS is the stability and consistent performance, especially when the disk gets close to being full.
Would definitely prefer BTRFS to be stable over having additional features...