It took me the longest time to figure out how events were propagated to individual items from the game... I talked about that a bit in the other thread.
It might also be a good idea to include something in the help file as to what the main game files do, what can be added to those files, and what can be modified - files like game.script, game_daemon.script, base.inc, etc.
I was also surprised to find you could add your own methods to, say, the game object by using the method keyword. If you search for "method" in the help file, you get dozens of entries, none of which really jump out at a user to explain this functionality.
You might also benefit from some visual flow diagrams illustrating the order code is executed in (knowing specifically where the "point of entry" is in the scripts), and maybe a hierarchy of objects (like, I think Game is at the top, but I'm still not completely sure).
Also, this might be a bit off topic, but the tech demo that shows off the engine is kind of...iffy. I mean, yes, it showcases the technologies, but I'd think it should also make someone say "Wow, I can make something like this with Wintermute!?!" Unfortunately, it doesn't especially elicit that response; to be completely honest, I almost decided not to use Wintermute because I was pretty unimpressed with the demo at first. Even if it doesn't showcase any new engine features, a new demo with more professional production values might help "inspire" users who are just trying the engine out for the first time. You know, wow them a bit. If you're interested in updating this, I might have time to give it a shot.
But, yeah, otherwise, the forum support is amazing; I don't think I've ever seen a forum thread that doesn't get at least one response; you never leave engine users hanging, and I'm sure it isn't easy, but it's great work.