There is no point in bloating the spec with more normative stuff and raise the bar for implementations. One of the 'out of the box' things that we've been aiming for is to get existing LDP implementations.
Are you satisfied with the current section on subscription?
Is it that you want to see a normative section or just any section on it to begin with. If it is the former, I'm not sure how far we can take that forward. The latter is hopefully in the process of being ironed out.