Carrier air defense worked by breaking attacks apart in layers

Would British carriers have been better without 4.5-inch guns and with more close-range anti-aircraft weapons?

No; the 4.5-inch battery formed a necessary middle layer that broke up formations before close-range guns engaged individual aircraft.

Replacing British carriers' 4.5-inch guns with only rapid-fire close weapons would remove an important defensive layer. Fighters first dispersed the raid, heavy anti-aircraft shells then broke up surviving groups at longer range, and pom-poms and smaller guns confronted isolated attackers close aboard. The defense aimed to overload pilots and prevent a coordinated strike as well as destroy aircraft.