Are there any future plans to add penetration through buildings or trees? The way I'm looking at it it could definitely unlock more possibilities in your maps. Instead of just defaulting to the same brick wall you can start to experiment with a softer plywood/drywall. Not really looking at it from a balancing perspective currently, purely an option to give more decisions on the map creation side of things
#Bullet Penetration
manic mural
waxen sparrow
A reasonable penetration is needed, but let's hope it isn't Phantom Force level of penetration where you can shoot through the mountain 
In all seriousness, for example, wooden wall of tensa town building shouldn't have ability to stop rifle rounds
But make it so penetration will also reduce the damage