So my bottom line recommendation is: Get rid of this darn "internal" update stream if you don't use it!
I'd pretty much agree with that BUT I think there is a possible sensible use for it. If it were used as a last staging post for changes (after the review etc you referred to) that were about to be released, then it provides a last chance to test it with _really_ everything else it has to live with. Unit testing is a good thing and must be done but we've seen plenty of problems with unexpected interactions (what a surprise).
tim