Where the hell does this info comes from?!?!?
Never heard of not having rough seas...
But should it be so, huge immersion "a la Das Boot" killer for me! I just love rough seas and the atmosphere it conveys, and tried many time to mod SH3 or 4 to have way better depictations of stormy sea states! So that would be a very big concern now for me... but frankly, i've never heard of that! My bet would be rather stormy wheather will be in, with big waves but still with problems as to make it believable and threatening, just like in SH3 or 4.
That videos of deadliest catch do show an interestind depictation!