The idea of a japanese campagin is the best to come since they came up with the electric torpedo thinghie.
Considering the shooting galery that is the American Campaign and the harder and harder shooting galery that is the German one, this might be the most nerve raking one yet. Sneaking past a whole fleet to deliver supplies to a besieged commander sounds very very "silent"
. And taking out a heavily guarded battleship during a full blown Kamikaze attack... I'm drooling.