TL;DR
A device to point targets on enemy units and buildings that turrets will react to..What ?
It would be nice if there where a laser pointer device that can be carried by the player or mounted on a vehicle in the weapons slot. Then when firing at an enemy instead of doing damage it would paint the target as a priority and any turret in reach would attack it first. That way the player can direct where turrets will fire first.Like the normal gun there should be 2 modes of operation:
1) auto target firing (holding down space) will select the enemy nearest to the mouse cursor and paint it as target. Once sufficient amunition is on the way to kill the target it switches to paint the next one.
2) targeting a spot (holding down c) will cause all fire to be directed at the spot until the player stops shooting there. Given the travel time for rockets you may get a massive overkill or just shoot at dirt. But hey, if you want to just see pretty explosions ....
Why ?
When aliens attack in a wave or when attacking nests often the turrets will concentrate on the wrong target. For example they will shoot at a swarm of little harmless biters that can't even reach them because there is a cliff in the way. Meanwhile the spitters or worms destroy all the turrets. Instead the player could paint the spitters or worms as primary targets and take them out quickly leaving the powerless bitters for cleanup later.With the target painting device the player would also feel more involved in fire fights.