I would love to see an interface into the physics engine via InSim. I know this is not going to be something that would be a priority for Scawen, but damn it would be cool as hell! Allowing for something like LFSTweak, without having to reprogram the interface every time there is a new build of the game, would be pretty great for the community as a whole.
Giving us, the InSim devs, a chance to do things like DRS and the deployable part of the MGU-K / MGU-H would be amazing but would also allow for the game engine to know that it's being modified from an outside source allowing for proper checking of this information.