Such as , build the new system to check their efficiency, more teaching video for each counties DDs
for example, how to fight with enemy DDs, how to offer view for teammates, because the smoke it is important, but only DD, and british CA have that , so the smoke sometime can change the situation.
No one want to see that they DD have ability to fight enemy DD, but they hide . Or they use smoke in the wrong place just for them to fire, but you lose view.
I think you have a lot of experience that , enemy DD all alive (or just die one)and they play well, but yours DD all die , so you will have a lot of pressure , because you need to consider the torpedo.
so the duty for DD is , the main source of torpedo, support the smoke and view, dislodge enemy DD(except CV）.