That would indeed be amazing. Kind of a silly question, but having the world as a sandbox at your disposal has to be a game developer's dream and while it's technically very ambitious I have to wonder why nobody seems to be making any use of the fact that Outerra is trying to provide exactly that.
A random gigantic game that simulates absolutely everything doesn't let you do that.
Take KSP as an example, sure it would be pretty to use that engine, but that's it, it would just be prettier. It would'nt bring anything new. The game is already fun, not because it's realistic, but because it has much simpler orbit mechanics than reality. A model a regular human being can actually wrap his head around.
The most boring and disappointing part of KSP are the contracts. Why? Because they are random. They have no direction and no sensible progression. They don't encourage you to push the limits. They are just an endless generated generic grind.
[1] http://forum.kerbalspaceprogram.com/index.php?/topic/91625-1...