Vectorflight 3d capability
The current crop of VF planes are definitley not for 3D. Things like solid balsa tail surfaces and thin airfoils make them great aerobatic airplanes, but take them out of contention as a 3D model.
Apparently they are designing a new Extra though that will be larger than the current offering, with some customer feedback, perhaps they could figure some 3D antics into the plans...