In a previous wishlist thread about subs, HiTech gave a rough idea on how he envisioned subs working in game and it was sort of along the lines of what you wrote.
ack-ack
I still say it would also require something not as simplistic alongside which is player controlled
asw. Not so simple, that. Sonar would have to be modeled, as would depth charges. And that's
just the basics. Does the AI sub stay at periscope depth? Does it 'dive' to its max depth when
being attacked? Or does the submarine 'task force' commander tell it to dive to a certain depth
as well as change it's course? Will the TF commander be the one ordering the torps to fire or
is this like a manned gun (fore and aft tubes .... but one direction the scope can view)? Does he
get infinite torpedoes to fire? Does the periscope get an icon?
Is all that really worth it to see a periscope and a bubble trail?