A few thoughts to add to the mix.
Either you like sub sims as much as I do, or you are in the Navy
but only because Aurora is a fleet game rather than a single ship or small task group game (such as Sub Command). If I was writing more of a tactical game then I would love to include many of your suggestions. I need to try and find an abstract level than provides fog of war but doesn't present the player with too much information (based on the fact there could be dozens of hostile ships), or too much micromanagement.
As an aside, have you read the Deep Sound Channel series of book by Joe Buff? I think you would enjoy them as they really get into the intricacies of underwater detection, in this case during a nuclear war at sea. There are six book in the series.
Steve