So I was thinking (again), but I'll skip that part this time, and just say what if there was a bomber plane (say, in the strider hub, or elsewhere if that's better) that dropped depth charges? There isn't anything in the game quite like it, and it might be interesting to see a plane drop a depth charge into the water and have cool explosion effects (because explosions under water look cool).
I was thinking though, that the depth charge could drop from the sky sort of slowly, so like, a little slower than the raven bomb or something. This way, units on land could escape some of the closer AOE, while once it hits water, it would roll towards (but not too much) the unit it was targeting, sort of like Claymore does it.
This is just a random idea that I have no idea if it would be good or not, but it could also be added to the more units mod as well.