I'd much rather see the existing copter improved in multiple ways - Rust has an amazing control scheme for a virtually identical aircraft, it's much more controllable and maneuverable. I don't understand why 7D2D has to have such a poorly implemented vehicle control for it. It's just painful to fly, land or take off in.
I'd see another version with two engines that might be somewhat more stable and have a higher inventory capacity at the cost of speed and fuel consumption.
Perhaps a version with armor plates to protect against vultures and vomit zombies.