If you want to revive the battleship I think you need a very strong anti-missile/aircraft defense coupled with an offensive capability with more range than the old-style cannons that is cheaper than an airstrike. Either lasers or railguns have the potential to be able to destroy any missile or aircraft approaching a ship with a very high degree of certainty. If you then had larger railguns throwing a large projectile that was cheap enough with enough range...you potentially have something worth building. It is a balance. At a point, it makes more sense to build flattops and pack them with drones and UAVs because you can hit a lot further away and the cost is not that much more.