Why the Revenge class offered little reconstruction margin

What sort of reconstruction could the Revenge-class battleships have received instead of the Queen Elizabeth class?

Only a tightly constrained reconstruction was realistic because the Revenge-class hulls lacked the internal space and margin that made the Queen Elizabeth ships better candidates.

Physical space inside the Revenge-class hull is the decisive limitation. A reconstruction would have been much tighter than the Queen Elizabeth programs, leaving less room for machinery, protection, sensors, and improved habitability. Hull volume helps explain why navies modernize some contemporaneous capital ships and not others.