Oh, happy, happy, joy joy.
OK. Can I start from the assumption that we're talking about a mixing room designed specifically for mixing film audio?
If so, what I'd like to see is for the interface to visually represent the three dimensional illusion created by the movie and then allow me to plot the sound for various speaker configurations.
Basically, if I have a jet plane come in from over the horizon and then fly at fifty feet over my character's head, whilst he screams "Hit the deck"... I'd like to be able to plot the sound's source as it travels in 3D space and have the computer figure out what adjustments need to be made to the sound to create that audio illusion for various speaker set ups. (5.1, THX, basic stereo, TV speakers and a headphone mix)
I think that this would involve having a grid at 90 degrees to the footage, where I can plot the depth of the sound within the sound scape. I'd also have to be able to key frame this, in real time.
I think the best analogy is the Motion interface... but for audio and 3D... and then mix that with all the capabilities and ease of use of something like abelton live 7.
And if you build it, could I have a free beta version for the Mac to test for you?