Subs overpowered

After playing several rounds I have noticed everyone seems to have the same strategy build subs set them around your coast use them to detect invasions as subs take forever to kill even with destroyers and naval bombers. Subs are overpowered and or destroyers, naval bombers are under powered. When everyone uses a similar strategy it illustrates a lack of balance in the game. Please nerf Subs or boost destroyers and or naval bombers. For example, I had 4 subs attack a battle group with 4 destroyers 2 cruisers a battleship and an airplane carrier with naval bombers. While I did destroy the subs, they did significant damage destroying 2 destroyers and reducing moral to under 70% on the other ships. The naval bombers were almost worthless they killed one sub but took 60% damage to moral. The battle also lasted over 12 hours. I am not saying that subs should not have done damage to the group, but with naval bombers and destroyers that damage should have been much less and the battle should have been quicker in my opinion. Even two destroyers against one sub takes forever, and the destroyers take significant damage. Destroyers should counter subs this does not seem to be the case.