So as a lot of people (and myself in the past) have been mentioning, line of sight in compound defence is actually an issue but we can't really build high walls or anything like that to block off line of sight at the moment. (Although it would be really nice to have things that block line of sight from two directions but can still be cleared by grenades.)
A potential other solution could be "smokestacks", structures that function like a smoke grenade and block line of sight during a raid, which might force enemy raiders to come within your range to start shooting, cover and hide melee survivors in the haze (or even hide traps in the smoke!). You might have to dump some treated wood or foil/matches and other smoke grenadey kinds of things inside every time it gets used, but I'm sure it'd create some variety in defence.
Hell, it might be nice if decoy traps created a decent-sized cloud of smoke when they go off - might hide the presence of other traps or stop enemy survivors from shooting at your guys until the smoke clears, as long as the DECOY issue is fixed.