Assuming that everything the author says turns out true - such as the "big one" exploit - in say an year from now, does anybody know any active popular open source distro that aims to keep systemd away from servers?
Removing systemd might have consequences for GNOME, but that's not a concern on servers. There is a significant enough anti-systemd contingent in Debian (not to mention Debian also supports kfreebsd, where systemd doesn't run) that I'm confident sysvinit will remain a viable option for servers and non-GNOME desktops on Debian. Even GNOME desktops may work on Debian without systemd thanks to the work being done on systemd-shim.
Well I gather that is the intention but there are a few bugs at present around that and an ongoing issue about upgrade from Wheezy to Jessie changing the init system silently. See Debian-devel for gory details.