That is a good point, in that at least with Silent Hunter III, you knew the Allies were going to get better and better at combating the submarine threat. The thing I am looking forward to though is the campaign, and specifically the dynamic mission updates. See a plane get shot down, and suddenly you're on pilot rescue detail. The waters are supposed to be more alive in this installment. Apparently the more success you have, the more dangerous and aggressive your missions will be.
At the same time, it is a video game and I'm sure they'll continue to do things to make things challenging for the player. I have played other Pacific Theatre submarine games and they were always fun. I hope (though don't expect) the "dynamic campaign" to be truly dynamic. But at the same time, I am just one submariner, so my influence shouldn't be super significant. Just something to show that my successes and failures have some sort of an impact would be neat.
Alas, I have not.
Since I, or anyone else interested in the Silent Hunter series, clearly do not feel this way, all I can say is I don't care what you have to say on the subject.