Since original reasons for existence of /sbin, /usr/sbin are long gone, a future EAPI can include changes towards not installing files into /sbin, /usr/sbin. Specifically the following things are in scope of PMS: 1. econf() should pass --sbindir='${exec_prefix}/bin' to configure. 2. dosbin and newsbin should be banned.
Not going to happen anytime soon. Feel free to reopen once the FHS doesn't mention /sbin and /usr/sbin any more: https://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch03s16.html