I am not versed in naval architecture or construction. (That's a nice way to say that I'm ignorant. ;) )
My impression is that modern naval vessels are thin-skilled eggshells in comparison to their WWII predecessors. Back then, armor mattered. Somewhere along the way, someone thought, "heck, it'll just get nuked, why bother with armor?"
It's cheaper to build and operate a lighter, unarmored, vessel than a thick-skinned one. So, the accountants won.
I would think a heavily armored ship would still be more survivable than a non-armored one, even with modern munitions. The M1 Abrams tank has an armor equivalent of over a meter of steel, in comparison to WWII's tanks having about 4-6 inches. Similarly, modern ships COULD be built with much greater protection than WWII ships.
I am always surprised, in a bad way, at how fragile modern warships are.
Just my thoughts, and I'm happy to be educated where I'm wrong.