Reading Ainamacar's statements about has me wondering a few things. When you load adventure tools, you'll see, other than the Monster Builder, there isn't much else. Perhaps there will be an Unearthed Arcana tab put in one day, which while compile the extra, fringe rules, in an easy to manage place (as it would be adventure based, thus Adventure Tools and be it's own tab all together).
Obviously, I'm just taking a shot in the dark. For all I know those tabs will never get filled or just be for more generalized campaign things. Also, I doubt we'd see anything like that for a long while, but it's an idea. I don't think it would be a difficult idea to implement. Just have the tab in Adventure Tools read something like this, "Unearthed Arcana: Optional Rules for your campaign" or something of that nature. And have it just be a compilation of the material.
Or, you know, nothing like that at all. Just ideas.