The main thing I'm drawing from the game, rather than the comments above, is that there will be certain ships that will be pretty useless to take, once this is released. For example Pensacola is a bit of a damp squib against subs (even though I sunk a sub in the last game), but Leander and Fiji at least can hit back.
I'm not against Subs, but I will probably never play in one.