I think that comparing SH from World War II to, say, 'Dangerous Waters' or even '688i' is like comparing apples with pears.
First off, the SH-series has created its own atmosphere. The player actually gets a bit of an idea of what it is like to be inside a submarine, and there is a huge sense of freedom. That gives the SH-series an advantage over Dangerous Waters and 688i. Dangerous Waters is 'just' moving from screen-screen to screen-screen - all very sterile.
I mean, put me in an operation room in a hospital and tell me to get sexually aroused, and I won't be able to get it up. Put me in a top-notch hotel room with a nice woman, and it becomes a whole different story. Dangerous Waters and its ilk are fun but they're operation rooms, while SH is that sleazy bar with two bisexual models-turned-porn actresses thrown in, and free booze to boot.
Welp, what I'd like, and what I've always favoured, is a remake of 'Red Storm Rising', with the fun of the Silent Hunter-level stuff (being able to move through your sub, actually being in the con etc) and the campaign-stuff of Red Storm Rising.
I mean, if you consider the fact that the Soviets back in the day basically wanted to re-enact Nazi Germany's U-boat campaign, but then not just isolating Great Britian but all of Europe, but then with about 200 subs more than the Nazis ever had, boy - that'd be fun!
Just imagine being in the high sees, approaching the sonobuoys fixed to the ocean floor (the Greenland-Iceland-UK-gap), ensuring you're not heard or picked up by a P-3 with its MAD dish, and then heading out into the Atlantic Ocean to sink US convoys headed for Europe, while you can see the progress of the Red Army while they crash forward into Western Europe...
Or commanding a Seawolf of 688 class, moving in silently through waters riddled with sonobuoys as you approach the northern coast of the Kola Peninsula to destroy Tu-22M Backfire air bases with Tomahawks...
As a side campaign, I can imagine being a Russki captain in a Whiskey or Foxtrot near Cuba at the absolute high-point (or low-point if you will), and just when you're surrounded by three US destroyers the chef in the back drops a metal pan on another metal pan and both pans just happen to fall on that one piece of floor where there's no rubber tiles...
Or moving into the Boomer Bastion to take out Typhoons after an Emergency Action Message flashes that Soviet land forces are suddenly dispersing from their bases within the Soviet Union amid high tensions - a tell-tale sign of something *VERY* bad waiting to happen...
Or the 'Armageddon'-scenario, where you're commanding your Ohio SSBN and *the* Emergency Action Message heralding DEFCON 1 arrives, while you know that there's at least one Akula out there somewhere.
And of course, after the Tridents have rippled and the tubes are empty, you get to sit back and pop a beer as you, through the external view or from the bridge while surfaced, watch the flashes in the distance, wondering about what kind of world awaits those who will survive the radiation, as "We'll meet again" is played
Yeah. I'd like that.