Installing a new system and using the --excludedocs option in a kickstart file's %packages section does keep docs off the system.  But it leaves empty directories all through /usr/share/doc.

The --excludedocs option for %packages is passed down to rpm's --excludedocs option.  I am not sure if this is desired behavior as it seems every file marked with %doc in the spec files was removed, but I would also expect the empty directories to be removed as well.  Especially given that rpm created that tree in the first place for the files marked with %doc