I doubt Debian requires systemd in order to work. However I do not see what your problem is with systemd, do you have an example of problems caused by the bloat?

It is very light on the system and a much better way to handle services that the old init scripts. If you want to reduce system resources usage I'd look somewhere else. You are likely to save a few MB of ram and some cycles of your cpu by removing systemd, but I doubt any significant amount.