If I understand it correctly, It would require a very large and complicated overhaul of the code for land, much like the argument going against submarines and the way water is coded now.
I think these surfaces are pretty much 2-D planes... and resemble wire-frame graphics. The contact model sometimes results in planes flying underground, or flipping ground vehicles.
Such a change is more appropriate for a next generation game.... and probably one meant for high-speed connections only. So long as the game supports much narrower throughputs, you are constrained on adding things like changeable terrain..... in this case you get a simple graphic that overlays the existing terrain.
