The Cleveland class's 6-inch and 5-inch battery mix

What is the drawback of the Cleveland class's 6-inch main and 5-inch secondary batteries?

Both batteries are useful, but their close calibres create a complicated arrangement; a larger 8-inch main battery might have made the ship's role and heavy-gun value clearer.

The answer respects the 5-inch/38 as a highly capable dual-purpose gun but questions pairing twelve of them with a 6-inch main battery. The shell weights and roles differ, yet the close calibres leave the ship carrying two large ammunition systems without the decisive reach of a heavy cruiser. Replacing triple 6-inch turrets with twin 8-inch mountings might have clarified the surface-combat role while retaining strong anti-aircraft defence. The conversion would require weight and balance work, but the Cleveland hull is presented as a plausible candidate.