A 1960s gun cruiser evolved for modern service

If a 1960s gun cruiser survived with a moderate missile load, what displacement and length might it reach today?

Probably around 20,000 tons, with substantially more missiles and radar capacity alongside its guns; no length is estimated.

A surviving gun-cruiser line would probably grow toward 20,000 tons. The estimate allows for a much heavier missile load, the radars needed to use it, and guns large enough to remain useful. Those additions would have to justify the ship's continued role. No overall length is estimated.