The naval situation hasn't changed at all, as others have pointed out. There were no changes to anything navy related this patch, but hopefully that will change in the next patch. (

hopefully not another 8 months)
For now, subs are utterly useless. Requires way too much micro to get minimal gain, and if you don't micro them to groups of 1-2 they do nothing but die.
In addition, Battleships and Carriers are OP and screens are useless. Don't bother building anything smaller than a BB if you can afford to.
However, Naval Bombers are the true kings of the sea. All important strategic naval zones are easily accessed by land based fighters and bombers. If you have air superiority over a sea zone it prevents enemy carriers form being able to launch planes at all.
So the best strategy is to spam BBs and cover all of your sea zones with fighters and naval bombers.