This game is not meant to replace the single player Silent Hunter games, you have to remember, Ubisoft had a team of 30 guys and a huge corporate support system for their game. In our case, there are two developers. They had a unique take on the submarine sim, where the game is played primarily with 4 guys as a crew, and the controls and actions are more manual than previous subsims. That's the target for this game, and yes, cooperative multiplayer is the key to the success of this game, because that's what this game is about
As for modding the game, first we have to make the game, you know.