I wonder about all the electronics. If a missile or EMP hits the island does the ship (big or small) become just a room temperature iceberg? Bigger has an attraction for me in that it has more room for more state of the art defensive systems and a greater variety of offensive capabilities. The admirals just have to think out of their boxes, but is there really a chance of that?
Protection against EMP isn’t space intensive. It is detail intensive.
Carriers would be OK against an EMP. And they could handle a missile or two. Nukes? No idea.