systemd units that are small, simple, and call into a single script are usually fantastic. There's no reason for these scripts to be part of another init system

systemd units that are small, simple, and call into a single script are usually fantastic. There's no reason for these scripts to be part of another init system; but making as much of your code completely agnostic to the env it runs in sounds good regardless. I think that's the feeling you're feeling.