I'll look into adding a draggable map soon, would definitely make navigation easier. It will also be helpful for selecting targets once SLBMs and cruise missiles are in the game.
As for minefields, I have no immediate plans to add them but I might put them in sometime in the future. I don't know quite how they would work... if the player can see the mines, they're easy to dodge and there's not much point to them being there. If the player can't see the mines it's basically rolling a dice to see if your sub explodes or not, which doesn't sound like much fun.
