I absolutely love the overwatch cones, but if LOS blocking terrain cast shadows into them, they’d be even more awesome.
I see that you stongly want to explore that first person balliistic system and all that connects with it. Line of sight indicator in other thread, overwatch cone modified by obstacles here. Overall nice ideas. I would saw it as an more advanced option in settings.
Keep in mind it is all based on casting rays and calculation where those land (or where are effectively blocked). Such overwatch would be definitely more informative when we could see if our overwatch goes through that crumbling shack, or somehow between all the crates and barrels. But we talk about dynamic (all obstacles can be destroyed with enough power - and here comes also destruction physics) shadowing in 3 dimentional space. If many soldiers would overwatch the same area then it would be like many light sources casting in the same spot. Of course this is not real time game so not many things happen here simultanously but still it put some stress on calculations. Modern computers are quite powerful, but also please remember that turn base strategy games are niche genre. Most people who play this kind of games don’t really tend to upgrade computers so often. That is why it would be great that some of them could turn such featrure off.