Also SSDs implement an internal filesystem optimized for flash that emulates a block device to the outside. For this Kinetic Store, the controller would be quite likely even simpler.

There would still be a need for ssd specific wear leveling and trim logic in the controller though

Trim is not needed if the disc directly gets delete commands, while wear leveling is actually a problem of spinning-optimized filesystems and can be solved easier if the external representation is a key-value store of immutable objects.

Yes... given they use the same connector on the HDD, I'm wondering if they actually need to change the hardware at all!

The sprite breakdown identifies one core as managing the SAS commands, via DMA. Now how hard would it be to actually manage ethernet similarly, via a ARM core? If that's what they've actually done, that's really damn cool.