I kind of feel like the cooldown time between shots makes this thing way too powerful, even when set for the max delay.

My thoughts (do as you will):

A) Change the cool down setting from ticks to seconds (although, the model you chose to use looks like it should be capable of rapid fire)

B) Simply increase (or remove) the max_value for the cool down setting

C) Add a "reload & cool down" delay/pause after X shots. You can make this whole feature optional in settings, with additional settings to configure the number of shots and down time. The concept is after firing (for example) 12 shots, it pauses for 5 seconds. Lore wise, you can pass this off as the turret needing to reload the launch tubes and (potentially) allow the whole turret to cool off. Also include some logic so that if the turret hasn't fired for a few seconds, the shot counter is reset (avoids firing all but the 1 shot needed to initiate the pause, to then only get 1 shot off on the next wave...).