Ok... as far as I'm concerned
there is a "slight" problem for the DDs maybe. I'm playing the campaign in medium difficulty. In my last patrol I decided to attack military ships to clear my path home.
I found on south west of England a little task force of 4 enemy war ships.... aimed and shot to hit. One was directly hit and sank immediatly... the other ones.... well they just ignored the attack and went their way without searching or anything.
Also, when DDs tried to search for me after a convoy attack, I heard no pings at all, is that normal ?
EDIT
I am abituated with GWX where a destroyer starts pinging and when this happens your quiet dead meat if in shallow waters.