I had two aha moments.
First was that I really didn't want the filesystem to do logical name translation. It was simple enough to do in the program. So no way to have the kernel expand /usr/share/fubar/$USER/fu. While VMS' logical names were a cool wart on its filename stuff, the whole ball of wax had too many special cases for different device types, permission areas of logical names, logical name table nesting rules, etc. Simpler was better.
The second was the simplicity of the install... boot one file to prep the disk, one to copy a fs to the future swap system and a final one to get the ball rolling... for booting off of tape, on systems with no real memory, this kept what wound up in memory small enough to live in the sub Megabyte systems ot needed to work on... though once there was a lot more, this was left behind when you could just load one kernel with a ran disk to do all the setup... the different pieces of the install acted as a Koan for how Unix worked...
Warner