This may already exist....
However I propose a new type of framed door called a Ramp Door.
When activated the Ramp Door, which is a single plane ramp, opens/drops until it collides with something, which causes it to stop and stay open.
Activating the Ramp Door again causes it to close back up into the frame.
The Ramp Door may be invaluable for loading/unloading goods, people, animals and vehicles. (Would also look good).
Could also be used as a draw bridge.
So thats my suggestion. It may already be under NDA but if not I think it would be a great element to have.