The biggest , and only gripe I have on the 990 is the fact, if I want to access my 990 settings, I have to black out whatever I am watching On the TV.
I came from a HK635, which I still have,that when any adjustment is made, ie Volume, surround modes etc, could be seen at the bottom of the TV when making a change. When accessing menu options on the HK 635, you could still see the material being watched on the TV.
So I agree a heads up display would be my choice also.