Well, when I first learned of the lack of brightness/contrast adjustment issue, I found a
discussion in the archives of the developers mailing list that made it clear that they were
well aware of this shortcoming, but had no intention to fix it any time soon.
This was over a year ago. Last I checked, the problem was still there, although I can't test
with the very latest Intel driver, because it is unstable in combination with my X server (I'm
assuming that once I update the X server, it will get stable).