Dirtdart,
The 30k TT idea, although presented tongue-in-cheek, is actually a good one. With respect to "realism" consequences of 30k tank combat, I doubt that the GV game would be affected, unless HTC models the differing gravitational and atmospheric pressure aspects of 30k combat.
BTW, your cloud idea sounded good to me initially. However, after further thought, I became concerned that the only way it would work would be to make the clouds very low, and doing that would eliminate the vertical aspect of the GV game (i.e. climbing hills & mountains to improve line of sight). Eliminating the vertical element greatly reduces the interest level for me; kind of like an air combat game where all maneuvers must be made in the horizontal. Without the vertical element, the GV game is basically reduced to driving through clumps of trees waiting to be ambushed. Finally, as I mentioned above, AC can do plenty of damage to GVs while attacking horizontally, although they make themselves a bit more vulnerable by doing so.
But one good aspect of your thread is that it motivated Greebo to modify his TT, and I guess the cloud idea can be given a test drive in that map as well. So we shall see.