My initial plan will be to sweep the entire codebase looking for any methods or properties that have missing entries. Be that either no method description or have un-typed or uncommented parameters. Once those are done I can then focus on sections which need more detail.
If you have any specific sections of the docs that you'd like to see my tackle first then please leave a message here or email me. I also believe that we need to get Phaser into a position where it's possible to translate the documentation. This is an area I'll need some help with, as I'm not yet sure of the best way to handle translation of jsdocs.
Interphase writing has been going very well. I wasn't really sure how much content there would be when we started out on this journey, but I did a quick PDF generation test today. With just 4 articles included in the output it's already 86 pages. So I've no doubt the final thing will be close to 200 pages in size. I have to admit that surprised even me, but I really hope people enjoy reading it when it lands shortly.