Basically, I want to be able to place impassable spots that offer exactly NO cover behind walls so enemies have to face my killboxes with absolutely no potential cover.
And this is why it won't be added to the game.
Well, my other option is to slap down traps on all their potential cover.
Or design so they don't have any cover. If they can't see across your rubble pile they will shamble onto it and get shot. You just have to play with angles.
W=Wall R=Rubble
WWWWWWWWWWW
W RRRRRRRRRRRRRR
W RRRRRRRRRRRRRR --> Your guys over here somewhere.
W RRRRRRRRRRRRRR
W RRRRRRRRRRRRRR
WWW RR WWWWWW
W RR W
W RR W
Waiting for the day where AI will counter killbox if there is other options like going through a door. Else your guys need to have piles of rubble slowing them down whenever they leave ^.^
Killboxes get boring rather quickly, especially if it is the only way inside (like a mountain). I am not telling you how to play the game, though. Just my $0.02.
Once you get experienced, solutions become numerous, and your pawns can actually have some fun instead of hauling chunks all day long. Especially if you are in the open, static defenses can be overridden and as such are potentially wasted or even counter-productive (increasing the enemy's strength).
I much prefer elastic defense. That means well-equipped pawns and multiple small bunkers that use darkness as cover, corridors with manholes, etc. Always keep effective reserve to take over and hold the front while the main forces are being treated. I have battles that last for days - much more fun if you ask me. Turrets are fine, but better to have fewer plasteel ones that you repair behind cover than a dozen steel ones that just blow up the moment somebody looks them the wrong way.
ignoring the mention of killboxes for a minute, i still would like the capacity to dig holes. even without kill boxes trenchs and deep holes have the potential to be handy... more handing if actual fluid dynamics ever become a thing and flash floods happen
It's not technically har to add holes to the game. The problem is that enemy AI can't deal with obstacles like that. It would just turn raids into Tower Defense (and many players play that way already).
Actually holes might be considered same as walls. It would also make melee more meaningful since people need to climb out from holes to keep distance. Or grenades. A chain of holes or single hole would not be much different than an unmined rock to stand behind, except for the elevation that needs to overcome. Cover of holes would decrease by distance... I think it is really a reasonable thing to have and manage.
Of course not in the manner of "impassable pit"