The issue i have with this system is that what for me is front for architect(for example) could be top.
So we have for ALL faces a list of all options...
My personal preference would be Plane plus direction
XY+ for example would be XY plane with positive Z direction etc.
I think if we want it as easy as possible for everyone use current 6 options with maybe one or two more (less than 10) with last option other what activate a text bar.