1. All allies and friendly buildings should show up on radar for both teams. For example, for aliens, a green dot to represent a teammate would let a goon know it's not safe to pounce around the corner and end up TK'ing them.
2. For building defenses, it would be nice to have a translucent 3D representation of the range of defensive buildings included in the blueprint. For example, when you are placing a turret, the edges of a translucent blue sphere is visible around you to show where the edge of its firing range is. This would allow for much more precise and effective building.
I have no idea how hard either of these ideas would be to implement, but they both seem like things that have potential to very much improve gameplay.