A modern battleship built around power generation and missiles

What sort of battleship would you build if a supercarrier-sized construction dock were available?

A very large nuclear-powered ship with railguns and a large missile battery.

The hypothetical removes dock size as a constraint and asks what kind of new battleship should be built. The answer begins with a very large hull and nuclear propulsion. The power plant would support electrically demanding railguns while the ship carried a broad missile armament. Electrical generation and magazine depth become the organizing features of this modern capital ship concept.