Why ski ramps would hinder Second World War carriers

Would adding a ski ramp to Second World War aircraft carriers help or hinder operations?

Mostly hinder. Wartime aircraft grew heavier and depended on catapults or conventional deck runs; a ramp was not well suited to their loads and landing cycle.

Wartime aircraft became heavier and normally relied on catapult assistance or conventional deck operations. A ramp can help aircraft designed for short or vertical take-off, but it is a poor fit for a torpedo-carrying aircraft that needs a clear, predictable launch path. High wind over the deck could already make slow aircraft such as Swordfish appear to leap from the carrier. In extreme conditions a fast escort could even overtake such an aircraft, underscoring how different its performance was from the later jets for which ski jumps were developed.