As of now, 9-inch shells have the largest splash radius of 8, followed by 4-inch shells at 7, and 12-inch and 14-inch shells at 6 (according to the CCNet wiki). The large difference between 9-inch and 12-inch shells means that 12-inch cruisers don't have as much use when a 9-inch cruiser has a better reload, a greater number of guns, and a larger splash radius, making it just out DPS 12-inch cruisers and be just better. Cruisers are already very powerful with their large percentages of armor, ability to carry torpedoes, and decent speed, so nerfing 9-inch guns won't make cruisers bad, just more balanced when compared to the other ships. but. Buffing 12-inch shells will not work in this situation, as then dreadnoughts with 14-inch shells would be made into an even smaller niche.