Anyway I'm still gonna be saying that ground fire should stay. And any kind of realism pleading means jack shit in Sci-fi game where they can easily have "intelligent" ammunition for battle ships that instead of exploding on contact will explode after going through certain amount of armor or traveling deep enough underwater.
Anyway if people want to shake up the subs + navy meta I would rather go about it this way:
- Start by increasing the muzzle velocity of all t3 navy units to make their effective DPS higher than it currently is without having to increase their theoretical DPS. Part of why the current fights tend to take so long is due to ineffective weaponry on half the ships at long ranges. Increasing the muzzle velocity will make it so more shots connect even when enemy is microing his units, allowing for faster and more decisive impact of t3 navy when fielded early. Honestly this change is something that could be implemented easily in the next patch without breaking the meta/destroying the balance all together.
As for subs balance:
- Keep the ground fire as is.
- Increase the HP and speed of subs so that they are harder to hit and kill by surface units
And now for the clue of the program: Introduce depth charges to more T2 destroyers, Torpedo bombers and other anti-submarine units while making them useless against surface targets so that the DPS against frigs etc stays the same(obviously Aeon units would need some rebalance here)
This way you can make them more resilient against ground fire while having them still be squishy against normal anti submarine units like destroyers. This would also introduce more balancing levers in submarine balancing which you seem to want.
Obviously that only goes if we can make it happen by making depth charges aim at subs only or by introducing armor for navy that makes it invulnerable to depth charges.