Have you ever seen a single cannon fire in real life?
I have, they put out a lot of smoke. Imagine 20 - 70 cannons going off at the same time side by side. You aren't going to see a lot of anything but smoke. The NA developers did an awesome job in my opinion with the realism of the cannons. This should not be changed. It also adds the the risk vs reward factor. You risk shooting your cannons with the possibility of an opposing vessel taking the advantage of you, or the reward of a critical hit.
Do not change the smoke, it is spot on.