Concerning the DD's ramming me, I can be brief. I don't know if it happened regularly, I guess not, but I'll make sure that ingame it won't happen to me. For me the hitpoints should be optimised for torpedo attacks and torpedo attacks only. Guns were rarely used, and as Tater and Beery showed us, they did not much damage at all. Ramming ships or being rammed is not that common imho, so it should not be considered as relevant.
The way ships sink will perhaps never be properly reproduced in a computersim, but WernerSobe, Redwine and Leovampire are doing a great job in offering options to players. I believe this is an ongoing process and eventually will yield results.