Why purpose-built Courageous-sized carriers would be better

Would the Courageous and Furious conversions have been better if built as aircraft carriers from the outset?

Yes; purpose-built ships could eliminate conversion-driven exhaust trunking and reorganize the hull around aviation requirements.

A purpose-built carrier would not simply reproduce the converted ships' internal arrangement. Designers could route exhaust without running extensive trunking through the hangar, a problem that reduced HMS Furious's effective aircraft space. They could also reshape the hull and internal layout around aviation from the start. The result would be a substantially better carrier because the machinery, hangar, and flight-deck requirements would no longer compete with a battlecruiser structure.