That's fair: we don't alert users that these recommendations aren't adequate for building elaborate new signature schemes. We're assuming people are trying to solve the basic problems described in the use cases we wrote (remember, this document originates as a response to a similar thing Colin Percival wrote a long time ago).

I'll think about a way to articulate that. Obviously, we can't really offer advice on doing state-of-the-art signature schemes in a couple paragraphs, and would not be interested in trying.

On the other point: the 2015 version of the document addressed the point you're making (and recommended deterministic DSA!). I just think it's kind of dumb to design new systems with a DSA dependency in 2018, and so rescinded the recommendation.