I get Happy's angle, but it's just a weird setting issue.
Fighters act like something outta WWII, Korea, or Vietnam, but the big ships seem to be more like something out of the Age of Sail. Combined with the lore that loads some of the big ships with dozens and dozens of guns, it just doesn't add up.
So, if you wanted to bump up damage to get a more modern feel where a couple good hits from an anti-ship missile is all it takes... ok.
But you'll still be left with an odd inconsistency of 1 gun crew = 1 Minion group, as that feels more like assists over a grouping. You could just as easily arbitrarily GM fiat the gunner skill and ignore the minion angle all together, seeing as how the actual Minion rules would, other than the grouping to get skill, not even need apply.
At the end of the day you'll always have "bad" rules at this scale. When dealing with dozens of cannons there's only so much control and granularity worth investing in. Things must be cut. WEG tried to go all in and if run 100% pretty much any vessel can obliterate any comparable vessel on Turn 1. WotC boiled it down, but then got fussed at for not counting every cannon individually and instead just rounding off to "what a ship could reasonable be expected to bring to bear at a given moment." Now here we've got FFG trying to meet in the middle and getting flak over that.
Figure out what works for you and go with it.