If I add cruisers to the game, I will go to a 12-sided die roll to increase the differentiation in combat abilities between destroyers, cruisers, and battleships. With respect to AA fire, the Japanese were pretty bad when it came to ship-borne AA weapons, while the US cruisers were on par with the battleships. I allow for shore-bombardment by all ships, but only in support of an amphibious invasion. No battleships standing off shore and clearing the area without an invasion. No aerial attacks on infantry either except in conjunction with an infantry unit, whereupon the infantry get a plus 1 on their attack roll, similar to artillery support.
As a side note, the US refitted an older British Light Cruiser with an armament similar to that of a Fletcher-class destroyer, but with less automatic weapons due to top-heavy problems. The British rated it as an Anti-aircraft Cruiser. Just something to think about when defending against air raids with US destroyers.
