Is there something inherent in the A380 design that makes it less fuel-efficient, or is it just that the engines are of an older design than the newest planes?

Is there something inherent in the A380 design that makes it less fuel-efficient, or is it just that the engines are of an older design than the newest planes? I have read that the Boeing 747 sits at some local maxima in design space, and to get larger, the Airbus A380 compromised by having a higher wing loading. This would reduce fuel efficiency a bit.