Probably the best thing Cake could do (or any DAW company) is a step by step how to. You can skip the mechanical parts - getting your interface right, etc.
Just start with the simplest stuff tho. Chapter one, Craig records the rhythm guitar via DI. Very slow with all the necessary channels etc., with close-ups of screen shots and highlighting what is changed at each step. The first chapters would, of necessity, contain a lot of other info, like this is a track, this is a channel, this is what audio looks like on the time line. At the bottom, in a scroll or something, you could have the manual pages for the definitions and "more info."
Chapter 2, Craig adds a synth bass via midi. Chapter 3, Craig adds a simple virtual drum track with loops, including Audio snap. Chapter 4, Craig adds more rhythms via the matrix, sidetracking how one can do the early rhythm tracks ....
Each aspect of recording is added, until you have a nice, SIMPLE song recorded and even the simplest among us can grok how you at least input music.
Then start on a weekly "here's how we mix" topics, starting with track filters and how restricting the lows, esp., can help your finished track, then ways to add reverb, then busses as part adding reverb, etc. etc.
A new user could spend a few hours going one by one, and at least have an idea of how SONAR (and any DAW) works and where have an idea to look for the action they are missing. I always loved manuals, tho like a dictionary they are frustrating if you aren't even up to speed on spelling.
Cakewalk would have a structured learning environment new users could be pointed to while experienced users could point to Chapter 3, week 2 that contained exactly how to perform a function, rather than trying to explain how a feature works. And Cakewalk could "evergreen" the teaching series, adding new featurettes to Chapters or going farther in depth. And perhaps give users who know what they are doing space on the channel to add some of these more in-depth sessions, saving Cakewalk a few bucks.
Anyway Craig, if you had started 10 years ago you could have a cracking good "living manual" today.