It really depends on alot of things. IMO, you could do uber-realilistic accurate maps of terrain without ultra high capacities of storage.
A great example would be a very old flight sim: Falcon 3.0 and Falcon 4.0:
Respectively, both games had great accuracies for what they offered. F3 had great Iraq war maps on 1.44mb floppies.
F4.0 improved it greatly, offering great realilistic maps of Korea on a 1:1 ratio, including most of Japan and Manchuria on 1 CD-Rom.
Accuracy doesn't have a whole lot to do with a BD-Rom storage media, as alot of the things (mountains, trees, temperature changes, ect) can be done with proceduar synthesis (both 360 and PS3 have these).
But I do agree: Next gen systems need realilistic Falcon 4.0-like sims. People paid $200 for Steel Batallion controllers, I'd pay $200 for Falcon 5.0 on PS3 or 360.
Back from the dead, I'm afraid.
