In Combat Mission quick battles we have similar discussions about balanced time periods for "pick your own force battles" (eg. 1941 Eastern Front where the Russians have unstoppably heavy armor compared to the available Pak AT guns and German tanks). In the end, the only way for the game itself to retain realism (accurate TO&E's for time periods) is to have standing, generally accepted gentlemen's rules about not picking them with the purpose of creating balanced fights.
With regards to SUBROCS, I suppose in RL the reason a sub diver might not load all fourteen tubes with subrocs and and just keep launching them is because he is never quite sure of the entirity of the threat environment, and that tactic would leave him quite vulnerable to threats other than the primary ASW target.
When I dive in these contexts, I like to keep full situational awareness and not give in to "I know this is the only threat" kind of thinking that leads to poor overall tactics and etiquette.
I suppose the other way around this is for MP mission designers to severly punish subrocs swarms, somehow, but I'm not entirely sure about how to do that...
