systemd is incredibly Linux centric. In fact it intentionally doesn't even try to be remotely portable, because an explicit design aim was to expose all the cool stuff that Linux has, but wasn't getting enough use.
What I want is a solid system that does what it's supposed to -- start stuff -- in a maximally boring fashion.
While I prefer Linux in general, Windows does have some good ideas in some places, and I don't see any issue with using them.
systemd was in fact heavily inspired by MacOS's launchd. At worst, it can be said that complex boot managers will begin to converge on a design that actually works ~ MacOS did, Windows did, and now Linux has with systemd. The three have plenty of differences, though systemd is still closer to launchd than not.
And in actuality, it's very tweakable. Did you notice that the source code is open, for a start...?