I would like to question dropping support for ROOTPATH completely as reasoned
As a system admin I would like to be given a reasonably easy way to choose whether I want different PATH values for root and users, and what they shall be.
PATH and ROOTPATH should work as it is still described in the Gentoo handbook at https://wiki.gentoo.org/wiki/Handbook:AMD64/Working/EnvVar.
To eventually unset ROOTPATH in /etc/profile in order to keep the environment clean makes perfect sense to me, as no other gentoo package should depend on the ROOTPATH environment variable.
Gentoo packages which have to add PATH and ROOTPATH components in /etc/env.d/ should do so selectively.
Thanks for reconsidering.