I'm fine with battleships as they are. I wouldn't really mind reverting Cerberus range to 3.5K. I don't think that it would change the situation notably, except that it would make battleship combat even shorter and POB sieges easier. I would definitely love to see House Cerberuses, though.
PS: And yes, some heavy battleships need a buff. The Valor, the Redemption, the Tokugawa and the Marduk are fine. Others, although they are somewhat capable of winning against a lighter battleship, can do nothing against a cruiser that has a light mortar. They can be hit from maximum range, and they can't hit back. A BIsmarck, for example, is quite fun to fly against other battleships as it is a challenge, a manageable one though, but I replaced mine with an Elbe because it was useless against such cruisers.