"The Unix approach of doing one thing and doing it well"
You do realise that many things like SystemV do more than one thing and not very well?
Are you confusing the forest for the trees?
I have been using Systemd for two years now and found it superior in every way to SystemV/Upstart (which is what RH/CentOS/Ubuntu were using before)
This comes from someone who was very skeptic at the beginning, I started using it reluctantly (was forced) just to realize that not only it is good, but bloody well designed.
It is perfect? Probably not, but trust me it is way better than SystemV at managing services and dependencies between services.
Most of the extra functionality is optional, you use it if you want it, pure and simple.