On the bright side it's a wonderful safety blanket to say: "Well, at least I can keep this project in its cute infancy, where it is non-threatening, requires little of me, and is more akin to the comfort of eating my own vomit than the risk of going out into the wild." And it's certainly not complete enough for even an alpha test, because while I strongly believe in taking a mathematical approach to game design, one has to work out the aesthetics first and then use that craft to make the game usable by the players. It's surprisingly like fashion: You display an idea, or a concept, on the catwalk, and then tailors run with it to make it wearable, and then finally it's hung in mass-market department stores barely recognizable to you, but acceptable to the masses. And where it retains the concept in the transition, you have succeeded in communicating that idea to them.
Now when I had last sat down to fiddle with my prototypes I encountered the issue of terrain, specifically representing terrain as both abstract collections of values, and matching those to stuff that resembles buildings and whatnot. The objective is to make a system by which this space and its objects could be folded and stretched into different states, all with the equivalent value. And, oddly, despite making terrain, or areas of the board logically equivalent as objectives, I hadn't gone the step further and reduced terrain to its components. The notion being that instead of saying: You get a building with x/y/z (interference, difficulty, armour) you should instead get components, just as a Titan is made of System-components. Rather than making terrain into set types and attempting to value these complex objectives, I think it would be easier to consider buying into a certain amount of Interference, Difficulty, and Armour.
I think at this point it's also useful to determine the value of these things by their position on the board. The middle four squares on a board of 8x8 squares, for example, should be more valuable than the outermost squares. Which raises an interesting topological consideration: where game elements deploy in opposite board corners, the shortest route to each other is through the middle, unless moving diagonally is proportionally more difficult than moving horizontally, and the space is also more difficult to move through thanks to...Difficulty. Which brings us back to the board. It might be something to consider the board as a whole rather than as the sum of its sections, its squares, in order that players consider the board.
So here's something like a plan. The whole board is essentially Open Ground (1, 1, 1), but then we can give a multiplier of x1 to the outer 'ring' of 28 squares, then another of x2 to the next 'ring' of 20, then x3 for the next 12, and finally (4x) 4. Now that's a cost multiplier. That makes for a very arena-like shape, and players pay 4x the price for modifying the innermost four squares, 4x more than the outermost squares. There's also elevation of the underlying area to think about, which could be another multiplier. I like the notion of underlying terrain, enabling damage to open ground in the form of craters. And what happens when you blast a crater? A deeper crater!`