(Lung time lurker, I thought that I had registered a while ago ... )
I always though one mayor issue with videography is focus is always a huge issue. Getting it spot on, especially with erratically moving targets at close range, especially with short depth of focus is very tough. A game changer would be some way to make it much easier which would make it make it more affordable for smaller groups to be more creative while producing better output.
One possibility (which would be much more universal but would take quite a bit of work to implement ) would be to use a belt drive system hooked up the the camera lens autofocus. Sort of a follow-focus with possibility with counterweight as in car engines to prevent torque shift at high speed. The device would monitor the digital output of the camera's for critical focus and refocus based on lens profile. The area of focus desired could be selected via touchscreen, joystick, or even be pre-programmed. The speed would be limited mostly by motor speed. If you have a powerful motor (much stronger than one built into the lens, it would focus even faster than the lens' built in motor and more accurately than all but the most trained hands.