I don't see why nobody is taking the middle road here.
Why not strip out all the non-init.d stuff from systemd for now (I understand there's a light fork that does this already), add plaintext logging (easy), and see how things go (testing).
This is linux, and debian at that. We shouldn't have to deal with extremely beta ideas that change so many paradigms all at once. If they can do what I've outlined here, then we should give it a shot (not on production servers yet of course). If it catches on, then over the years we can debate how much to delegate to systemd and how much to do another way.
For one, I can see no disadvantage in keeping a plaintext log around. Sure, takes a little more space, but most systems are not that space-limited these days. Seems like it would be handy...