There could definitely be a lot of uses for such a system:

If wreckage can get in the way, you might choose to try to take out a unit in a choke point to disrupt movement.

If wreckage can provide cover you might position your units so that larger units can provide cover for smaller ones. You might use the wreckage of an enemy unit as cover. You might choose to move one of your units in an otherwise unintelligent way or fire upon one of your own units to prevent enemies from using it for cover.

If units have morale, you might have to ensure that weaker units avoid the wreckage from previous battles so they aren't lost. You might ensure your units pass by the wreckage of enemy units to improve their morale.

If equipment can be salvaged from wreckage, or if you can gain resources from it then wreckage can potentially be valuable.

It's something that's been done before in numerous forms, but I think it's certainly worthy of consideration.

This could be especially impressive with huge ships in low orbit crashing into the surface. Becoming a whole new part of the map and dynamic addition to the game since every time it crashed it would be different.

This could be an interesting effect. Asteroids/starships that crash to earth on occasion. There certainly are chances this *could* happen over an existing base, in the middle of a battle or next to some event. I'm thinking to maintain fun, it should destroy much. Unless perhaps there is value in it as an attack. Perhaps for some reason bombs can't drop from space. but ships can. Perhaps a colony can decide to sacrifice a transport ship to crash over an advancing enemy force. The bigger the ship, the more valueble it is, so this is more of a last ditch effort.

If units have morale, you might have to ensure that weaker units avoid the wreckage from previous battles so they aren't lost. You might ensure your units pass by the wreckage of enemy units to improve their morale

Good call. I think that's quite reasonable to have an effect on non-veteran status soldiers

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This gave me an idea for non-mathematical combat. You can tell if your troops are disheartened or emboldened, but not the enemy, and Vise Versa. This gives an element to throw off calculations. Typically you would not want to send a force into battle that was disheartened, if their ability was reduced. Of course this could also mean that a soldier's drive is increased if their early experiences are positive, not just survived. Perhaps when these soldiers go through additional training, they (or some of them) might graduate early and be ready for more battle sooner.

They could also burn for a while, creating a visual obstacle to your FoW.

If there is a large battle with tons of units getting destroyed, it would probably be hard for you to see minor enemy activity in the middle of it all, or lets say enemy aircraft flying through the smoke clouds.

[quote name='Waterlimon' timestamp='1357652896' post='5019031']
They could also burn for a while, creating a visual obstacle to your FoW.
[/quote]

I like that. I had been imagining more along the lines of Blown Apart, but set on fire is good too, and both is better. Then you could also create incendiary weapons, and set a path on fire. It can be put out with a short amount of time, or an agent specifically for stopping the fire. But that would also set traps to separate troops out, by having preset fire lines. anyone directly over it, too bad for them, and then with individuals in between the fires, they are sitting ducks. Easy targets, unless they run through a wall of fire taking serious damage.

Also, fire could have a range damage while it is going. if are in it, it is terrible. right next to it, depending on the size, it hurts a little to a lot. and a space or two away and your fine. Also, the idea that fire can spread seems like another usable map feature. Flammability of buildings and map features like trees.

[quote name='Waterlimon' timestamp='1357652896' post='5019031']
hard for you to see minor enemy activity in the middle of it all, or lets say enemy aircraft flying through the smoke clouds
[/quote]

Smoke is another good aspect of fires. allowing low/no satellite vision. I also like the idea of deploying satellites for visibility. you can always see but only in a limited spot, even if you have no troops on the ground in that area. you can deploy multiple satellites, but they cost a lot.

But smoke, can hide forces. Also, adding natural fog, not FoW, but fog literally Just happens. But can also be artificial, though the wind will be random. once its in your favor, start fog machines, then send in troops under its cover. Satellites can see you, but ground units probably won't.