Not like anyone reads these things, but here goes:
No one, including me, has been working on the docs very much lately. The main reasons for this are 1) we're all busy with real-life stuff, and 2) ZSNES is in heavy development, and it's kind of pointless to try to document something that is in a constant state of change. That said, there are of course parts of ZSNES that are unlikely to change, but could be documented better. However, once we are vaguely close to a feature-complete official release, we will be thoroughly documenting it.
On another note, I'm really glad to see the WIP docs from the web site being linked from the ZBoard. That's what they're there for.