A better view system, recording all sounds, recording tracer fire.....but mostly...I wish for 2 things.
1) The ability to take control of your aircraft while the film is running.
2) The ability to create a drone that flys the EXACT flight path you originally did.
These two items could easily be the best trainer out there. AirWarrior's film viewer had these things. I used to d/l other peoples films and would watch it once, then turn on both of these things and learn how others performed different maneuvers.
Can you imagine telling a new guy to watch and participate in a film that shows a rolling scissors? That is a very difficult maneveur to describe. It would be so much easier to be able to follow a drone through the scissors. :-)