What 'twenty years ahead' misses about the G3 and N3 designs

Are the G3 and N3 designs called 'Iowas twenty years early' because of their capabilities or because of later perceptions?

Mostly because of later perception; the analogy is convenient, but the ships differed substantially in speed, subdivision, and role.

The comparison is a postwar shorthand that helps readers picture the ships rather than a literal technical equivalence. N3 would be slower than the later American battleships, while G3's speed and subdivision place it firmly in the battlecruiser category. The analogy remains useful as long as it does not erase important design differences.