Another point I'd like to make is that while there have been great efforts in WWII sub sims done so far, we're well away from even having all the gameplay features we might like! There's a lot that still could be done in the gameplay-relevant graphics department (drifting rain squalls while intercepting a convoy, anyone?), AI department (don't get me started on this one...), let alone the campaign department (a true dynamic campaign with a strategic AI, anyone?)
I think with all the new technology we get, we deserve the WWII sub sim genre to be updated every couple of years. And noone has done it better than the SH series.
I sincerely wish that SH remain a WWII series. How about for modern, someone ressurects Fast Attack instead?