The breakage is annoying but we could, at least in theory, end up in a situation where all distributions use the same /etc/tmpfiles.d configuration method. IMO that is worth a bit of pain. Particularly when the new method is better documented than the old one: I don't ever remember hearing about /lib/udev/devices until this discussion: for whatever reason Debian doesn't even use it, it has its own /etc/udev/links.conf file that explicitly says in its header that "This file does not exist. Please do not ask the Debian maintainer about it.", etc.
OTOH we could end up in the situation evoked by http://xkcd.com/927/. Maybe it's naive to be so optimistic, but a world where everything in http://www.freedesktop.org/wiki/Software/systemd/Interfac... is adopted by all distributions would be quite pleasant: a world where you could configure all this low-level stuff on any distribution without having to deal with all the pointless differences between them.