I think that the Roma need to be in top 5 ... she was the most modern ship in 1942, not only for the protection scheme, but the Roma had also a sort of "computer" (made of maccanic calculators) to get the coordinates for her heavy cannons faster than other ships! She never fought but on peper she had the higher probability to get the first shoot in a naval fight ! I think she's not a battleship to understimate