That isn't to say it's been all rosy in Gentoo-land. It was an effort to keep Gnome3 off my system, to keep the existing Gnome2 versions of everything until MATE (and the Gentoo community packaging) was ready enough to replace Gnome2. But my system is happily free of Gnome3, systemd, and pulseaudio. And because Gentoo doesn't really have release versions, I can keep my other packages up to date indefinitely.
One can already see how you at least have to keep the libsystemd package installed on Debian's latest, even if you use something other than systemd as the init etc, or else apt throws a tantrum.
http://ewontfix.com/15/ may be the most interesting read in all this. Notice how everything but dbus and the systemd lib have various issues. And if kdbus hits the kernel, systemd is poised to position itself as the mediator between (legacy) dbus and kdbus.
All in all there is some serious "one true way"-ism coming out of the systemd camp.