It was abandoned by upstream, just killed in Fedora because of that: http://pkgs.fedoraproject.org/cgit/systemd-ui.git/tree/dead.package
At the very least, the post-install message of sys-apps/systemd should not advertise sys-apps/systemd-ui.
Package removed. (Was already lastrited) commit 3a0a6849df5ba6ef18243b98ac317de03e3473f2 Author: Dion Moult <moult@gentoo.org> Date: Thu Sep 24 19:29:34 2015 +1000 sys-apps/systemd-ui: Removal after last rites. Bug #546192