I agree WHOLEHEARTEDLY with Manny here, Gary.
Your point about the roads being cleared off from time to time is noted, but while it seems at first breath to hold water, it really doesn't in this case, IMHO.
I think you have to realize that you are supposed to be creating ART here. "Art" being not-necessarily bound to the hard-and-fast maxims of reality. Look, you could do a five-square-foot dio of a tank sitting in the middle of a farmer's field, with 4.5 feet of nothing but static grass and straw around the sides of the tank, and still argue that is entirely feasible and realistic. But you'd be missing the point there, as here.
As protection, firepower and mobility are the three legs of the triangle regarding a tank's success, so are subject matter, composition, and skill of execution the tripod of a successful dio. You certainly have the former and the latter, but in composition, the dio is lacking. You definitely need something to balance the building in the corner there.
Here's the good news--and it has nothing to do with "Geico"!--alll that empty space will be a cinch to fill with another secondary vehicle, or even a cool piece of something; a part of a wall, a cart, a mounted cavalryman or field kitchen limber--something!
Something else you might well-consider in the future for your dio's; NEVER, EVER "square" your roads, buildings, etc, (the major pieces) parallel with the edges of your base (as you've done here). It's MUCH more visually-pleasing to slightly skew the lines of the your scene by placing a slight angle to the major pieces in relation to the edges of your base. Look at other successful, well-known dios, and you'll see that this is invariably true.
As a last point, the work in this dio IS extremely well-done, and I must say that the paint and build all-around is excellent!