Maybe to buff/change how the turrets work, at higher burst fire levels or with each burst fire upgrade they fire more at once instead of in a barrage? With high enough cooldown and enough burst fire there are lasers constantly firing but they cant keep up with lategame rockfall/skulls etc. In line with that if keeping the barrrage from the burst fire upgrade, maybe make the cooldown work so they can fire another barrage while the previous one is still going on.
I am not quite sure what you mean in regards to burst/barrage, because yes after a point the burst basically becomes constant automatic fire. No bullets get wasted. But I do agree the turrets can't keep up with late game rocks. You need laser cannon shielder aura to contend with that. In the future I will add more ways to protect runners, as well as turret upgrades. I've been thinking of giving turret a chance of firing rocket salvos, and/or upgrading a turret into a kind of beam-rail-gun that hits/pierces every rock in a straight line.