This means that some Debian packages could require users to run systemd on their systems in theory — however, in practice Debian still works fine without systemd (even with e.g. GNOME) and this will certainly stay the case at least for the next stable release Jessie.
However, the controversial general resolution proposed late in the development cycle opened many wounds in the community, prompting some prominent developers to resign or leave altogether, stirring strong emotions — not due to adoption of systemd per se, but because of the emotional burn-out and shortcomings in the decision processes apparent in the wake of the systemd controversy.
Nevertheless, work on the next stable release is well underway and some developers are already trying to mend the community and soothe the wounds.
[In case it's relevant, my system is a Lenovo X220 laptop, with Debian jessie, kernel 3.14-2-amd64. I run fvwm with an ancient config.]