I was thinking why not also go all the way and also measure the 3d distance as well. If we know the position of the ships mathmatically, in this vitural 3d space, would it just be a formula easy applied for distances between objects? I imagine some of these scientific calculators availble on the web could easily do a programmed formula like that to give you distances for sensors and combat. Hmm what math would be needed to define such a battlefield, trig?
The math for 3D combat in a "Mayday" style game is no different, there's just 1/3rd more of it.
You don't need trig for the same reason you don't need it in Mayday. Since the basic movement system is that you move your future counter anywhere within N "G's" of its location, you simply need to allow a Z direction and make sure that your delta vector is within spec.
The only real added math is sqrt(dx^2 + dy^2 + dz^2) to calculate distance, vs just using dx and dy. And with 2D you have this handy grid so you don't have to do any math at all.
3D is important in games like aircraft fighting games, because changing elevation has costs and benefits and are part of the performance characteristics of the plane.
But if you really think about a generic 2 ship battle, that battle in fact operates in "2D", even in 3D space. 2 pts define a line, and a line is a 2D element.
The only things that really matter in combat are range and facing. Airplanes fight in the gravity well, and have aerodynamic surfaces, so facing is difficult for them to change.
But in G free space, given appropriate thrusters and such, facing isn't a problem at all. Rotating the ship around any or all axes is basically trivial.
So, if you have 2 ships staring at each other, and one decides to rocket straight up, it's no big deal for the opposing ship to maintain the same relative facing towards that ship, and what you end up with is rather than getting any benefit of the 3rd dimension, you're simply increasing the range slowly. If you wanted to increase the range quickly, you'd go in the opposite direction of the ship, and that can be done in 2D.
Now obviously if you throw a 3rd ship into the mix, you now have a 3rd dimansion to work with. But you can see how the 3rd dimension does not really add that much to the game, but it adds a lot of complexity. You you have to keep track of the facings on a sphere vs the facings of a hex on top of the difficulty in representing 3D on a tabletop.
The best 3D game I've see was a dogfight game using airplane models where they were clipped to 8 foot tall sticks. Essentially a miniature WWII dogfight, and (as I mentioned before), the 3rd dimension is very important in a gravity well.
The big benefit of this is that at a glance the players can see the real relationship between the units. On a 2D map, you can easily have a ship that appears to be standing still, yet is in fact increasing/decreasing his Z axis. In heated battle, since the marker never "moves", it's easy to lose track that he's moving at all, only to be surprised when you find out he's only 2 hexes away and not 10 "like he was before". That's a very frustrating game experience.
But for most in space games, the 3rd dimension adds more complexity than actual "gaming" value. Sure it can be more "realistic", but not that much more fun or tactically rich. It's not like you can come out of the sun or break through a cloud in surprise, it just gives you more facings to cover, but 10 facings isn't that much different from 6 facings when it all comes down to it.