Honestly? We need not a successor of FHS but of filesystems, who are intimately tied package managers and installers. Zfs timidly start the change, with IPS (Image Package System) and BE (Boot Environments, as zfs clones), and we need to go much beyond that instead of wasting resources keeping up an '80s model like some do from btrfs to stratis.

We need:

- query-able storage, because search&narrow is the current way of accessing information and collecting/transcluding data is the way to go;

- easy storage management, the "rampant layer violation" of zfs we really need;

- integration of such storage to the software stack, from the OS to single packages, it's a nonsense having to "spread" archives in a taxonomy to deploy them or downloading archives to be unpacked as well for updates when we have send-able filesystems (zfs send of snapthots) and binary diff (from a snapshot "tagged version" of a fs-package to another, sent over internet).

Unfortunately we need operation people together with devs and nowadays operation is nearly disappeared. Devs alone can't understand what we need, they can't go beyond their desktops in a mass large enough to avoid a positive evolution.