Hi Mike,
I'm glad to help. A really cool tool like X2go deserves a really great documentation. I am always amazed how few people (especially here in the Westcoast of the US) don't know X2go.
I have been using it for a long time now, but might be a little shaky in the internals. What I am good at though is seeing both the developers side and the users side and be able to bridge it in documentation.
One thing that I would think would work great is to have an into page in the wiki, called "New to X2go? Start here! What is X2go and what does it do?"
I would write a little thing there about how Linux was basically always the perfect Terminal server, BUT no easy free framework ever existed to use it. That we used to envy RDP on Windows and that we now got the same thing and much better on Linux. I especially want to point out what it can do (like thinclient support which is super cool). On some details I might have to ask you a few things, what what is, since I have seen that you added a ton of new features that I am not even aware what they do (I for example never used the desktopsharing function)
I would also like to do a bit there where I do a little FAQ like: I got X11 forwarding over ssh, why do I need X2go? (A think I hear all the time from people) and point out what it can do more.