Well, there really isn't much to say. I think hiding the navigation is very good. In my experience with the new interface so far, I rarely need the navigation. That's why it wouldn't be a problem for me to hide it.

Sometimes when I visit a user's profile page and want to look at their comments, I have to think for a moment about how to access the comments. This might be even more unfamiliar if the navigation is hidden, but I don't think that's really a problem.
That's why I think you should implement it like this... after you have thoroughly brushed your teeth ;-)