After the release of K2 v2.10 (working on doing that before the end of the month), I do plan on switching to a new documentation format for K2, based on GitHub. It will resemble this format:
docs.joomlaworks.net
I will surely move some of the documents already on getk2.org (which are up to date) and I did plan on creating 2 guides to populate the docs. One for end-users/admins and one for developers. Since K2 resembles Joomla's article system in many things, end-users never really had an issue grasping how K2 works. It's usually the pros and devs that required some extra digging around which I hope will change in the coming months.
If you'd like to assist with the end-user guides, that would be great. Let me know for that so I can create the repo on GitHub to get this started.