Even at this 3-line stage, the stateful log.SetOutput construct is ugly and error-prone. So I'd say a functional/immutable language would already be adding value, and that would only increase as the amount of code grows. At a minimum an init is going to involve parsing config and something similar to a state machine, both good use cases for functional languages.

When C is taken as the baseline, there's a very long list of languages that look better for this sort of program. I don't see a huge reason that init has to be C, or even particularly benefits from it. (Specific init implementations may have the advantage of being battle-tested, but that's a characteristic of the program and time, not implementation language per se.)

Using high-level languages for init systems is a great idea. In fact, we do this for the Guix System Distribution. Our init system is called GNU Shepherd, and it's written in Guile Scheme. It's great because you write services as Scheme code. For example, I have a number of Ruby web servers that I run for development at work that are nearly identical. Since services are first-class Scheme objects, I wrote a simple function that returns a service object for running a Ruby web server, specialized for a given application. For this workflow, I run Shepherd as an unprivileged user and additionally manage all of my user services like gpg-agent, emacs daemon, offlineimap, etc. No crappy external domain specific language to learn; data is code. Highly recommended.

http://www.gnu.org/software/shepherd/