... and I thought that it would make for a really amazing zone- a (relatively) low altitude fighter battle arena over the war-torn surface of Balmorra.
From a storyline perspective, it would really tie the two game elements together, I think. Some would look up from the battlefield of Balmorra and think "That's what it looks like when I shoot by in my fighter", and those in the fighter scenario would look down at the surface and think "Wow, zipping by over the ground like that really gives you a perspective of the speeds of this combat".
Additionally, having all those terrain models already created would help reduce the time it would take to build that new scenario. Not sure how it would affect the current game engine, with having a flat plane as a limit against travel like that, but it would be award-winning IMO if you could pull that off!
Just a suggestion for something new down the road.