Hard to say. I am sure the USN never thought the Battle of Suriago Strait would happen either. The US Navy was vulnerable to intermediate size ship attacks in the 1920s, like most major navies. The Sara and Lex would have had to rely on a bunch of 4 stack destroyers to protect her from a much improved Japanese destroyer force in the 20s and into the early 30s. As I said, the Omaha class cruisers were ok but were designed to scout for the BBs, not the carriers.

In addition, the capabilities of carrier aircraft were much less than they were by the late 30s and early 40s. It is pretty easy to rip on the capabilities of the TBD but compared to the biplane aircraft used in the 20s and 30s it was substantially better. The old SBUs and XBGs used on these ships were limited in their range and capabilities and the Navy feared that a determined enemy in force wouldn't be deterred by these aircraft. Plus there was a fear that the carriers, if trying to transit the route to the Phillipines, could be caught in a pincer from the south and north.

And you are right, they wouldn't be the equal of full blown cruisers, although they still had the speed and armor (for the most part) of a battlecruiser. The issue would have been gunnery ability, something I am sure wasn't practiced to the precision of the all gun cruiser teams. They would have been ad a disadvantage for sure.