Currently openrc depends on ( || ( >=sys-apps/sysvinit-2.86-r6 sys-process/runit ) ), which means that sysvinit will be uninstalled if runit is installed and in the world file. This would be fine if runit provided the same functionalities as sysvinit, but by default it doesn't: most notably it doesn't install a /sbin/init. Contrary to sysvinit, runit can also be used standalone (not as the init process). That seems to be the usecase provided by the current ebuild. Openrc shouldn't depend on runit until the ebuild can install runit as the main init system. Maybe the runit ebuild should have a USE flag to govern that behavior, and openrc can then depend on runit installed with that useflag. Bug 575478 might be linked to this one, I'm not sure.
OpenRC should not have a dependency on runit; the reverse might be true and should be taken care of in the bug you cited above. The live ebuild has been updated to not depend on runit in commit 51c8592. This will be affective with the 0.22 release.
