i haven't done any gem stuff for ages...being more interested in the audio side of things....but this might kick me back into action on the visual front.
some kind of 'sequencer' would be nice for the video.
definately include as much audio-interactivity as you can. ideally you want to be able to trigger video events by audio events such as drum beats...also by midi input...and then the best would be the option of using audio signals to generate video.
also, it would be important for me to be able to feed in the output of my own patches to the video stream.
and then to be able to take video from the stream and run it through my own processes before sending it to the final mixer.
i'm looking forward to this now.