Why a larger Clemenceau would not automatically be better

Would a 27,000- to 34,000-ton Clemenceau-class carrier have been better from the start?

Not automatically; the benefit depends on how efficiently the extra displacement is used in the design.

Displacement alone does not determine carrier quality. A larger Clemenceau-class carrier might offer advantages, but only if the additional space is translated into a more effective design. The watch point is useful for separating size from actual capability.