Any of this is subject to feedback, but I recommend that documentation be written so that it's first organized around logical topics - like templates, data, content, etc. Simply because it's easier to write in a linear way and and make sure you hit all of the bullets. After that, we can create paths for specific types of users via content, navigation, search and links, so that developers vs. designers, or newcomers vs. advanced users can quickly find what they're interested in, and the information for any type of user will progressively disclose in a way that makes sense to them.
- By topic (templates, data, ...)