My opinion is that the wish for a manual is an outdated reflex. "Here, 400 pages of the latest MC novel! Once you read it you can sing by ear regarding the subject!" I can't see that happening. First, it'll have so many links between sections and subjects that it'll
be a wiki. One will need to browse, to jump; turning page after page won't work. Second, I'm not sure what
exactly one would want to learn. If JRiver comes out and explains in long paragraphs what every little click does, it's still not gonna be enough. I'd bet (assuming mode here, guessing a bit) that what one would want to know is how 2 or more things work together, the synergy, the spiraling options, the creative ideas that can go in many directions (and that are often talked about over here). That you can't learn reading a manual. Just as you can't learn to swim reading a manual.
About the wiki. I believe it can be improved regarding "how" explanations are presented. I can't speak regarding the whole wiki but certain sections could use real examples, screenshots if necessary. I'm not the expert, far from it, but the entire Expression page seems wrong to me (remember, I'm not a programmer, feel free to show me to what degree I am wrong, if I am). I'd say the syntax descriptions are actually your examples and the real examples are missing. A real example would be every function applied to a real value, with a clear return for that case.
So every average John Doe that has just barely touched the function knows how it works, has a limited example with a clear, tangible value as a result, and can expand the logic from there. It's very possible that it's not going to have to read long explanations, because it can see the complete example. That is missing now. The syntax is there but not a tangible result to check the logic against, to see if the one learning understood the function or not.
And then Marko starts posting expressions and we all go home... to learn some more
Just the way I see it on a couple of subjects...