Not neglected, Meridian has spent quite some time trying to figure out how to make it work in OXCE - it's not so simple, otherwise we'd have it already.
Its actually very easy.
1) Make the attack roll like usual. If there's no target unit there they dont get any dodging benefits obviously but its still a % chance to hit for the soldier using the weapon (maybe we could even increase their chance by 20% or so because they're targeting a piece of scenery then, its abit presumptious to assume perfect accuracy even against something stationary).
2) If the attack roll fails then stop, otherwise progress to projectile stage.
3) Shoot the weapon's projectile with perfect trajectory.
The projectile may still hit something else in its path, if you were targeting a unit behind a wall it can hit the wall (though you could be targeting that wall anyway, adding an enemy unit behind the wall makes it artificially more difficult to hit that wall, but oh well).
Furthermore I think something like this should be available as an accuracy option for battlescape for regular weapons too, applicable only to units:
1) Check percentage chance to hit that target, if its 74% chance then there's a 74% chance to actually hit them.
2) If it hits, the shot follows a perfect trajectory to the target, no questions its a done deal, the trajectory to the target is just the projectile being rendered in flight thats all.
3) If not, trace a random trajectory based on what the accuracy usually means for shots. Except that if the trajectory results in a hit REDO it until you get a trajectory that doesn't hit the target (give it 10 tries maybe, if you're that close or they're that big sometimes its just hard to miss. I assume this calculation takes an abysmally low amount of CPU power to perform so technically it could be retried 100 or 1000 times, but it would need a cap to prevent a feedback loop).
Now 43% chance to hit really means 43% chance no matter how far away the target is.
I realize this makes combat more deadly but then it allows modders to actually lower the accuracy ratings for their weapons.
It also gives better life to Range limitations on weapons too, since that can affect their chance to actually hit without being applied to the natural accuracy of the weapon (so it affects the toHit % roll but doesnt affect the Trajectory Cone). Sorta like an ancient aliens professor pose saying "Im not saying it makes the weapon inaccurate, but it is going to hit the target less often"