Dang McHub, you got jumped on this one.
Here's my reaction: I've long wanted a multiplayer option to have multiple players in one sub.
My brother and i used to play SH4 with voice commands, one of us would man the keyboard and mouse for navigating the stations and what not...one of us would man the microphone to be the "Captain" and it was great fun.
Incredibly nerdy? Yes.
Incredibly fun? Also...yes, because I'm incredibly nerdy
Having a multiplayer option for multi-user-submarines would be amazing...
However I can't get aboard on a MMO. Too many pitfalls in that swamp.