They should have that mechanism for ignoring cover the close you are.
I mean how ridiclous does it sound for a squad that closes in face to face with smg's but the guy with bolt actions holds them off because he is a building!
It should be at least closer than 5 units. Still the building gives an advantage, but as much as it should currently now. Another alternative to at least counter in another way.
I mean it is quite self-evident in terms of urban combat, who should win that engagement irl. Not bolt actions close range but it should be smgs who win the initiative mainly when they close in.
Or ensure that Smgs have a bonus against garrisons.