Well the people who say the Iowa was wasteful have the luxury of basing thier opinions on the fact that the Iowa Class ships never went toe to toe with battleships. There is a certain design efficiency in the NC and SoDaks, but they were never going to be as fast as the Iowas. or the carriers. The NC and SoDak were treaty Battleships, whereas the Iowa's only design limitation was beam. Speed is a function of length to beam ratio, and the beam limitation was set by the Panama Canal.
On the wargames table, if the other guy is bringing Yamato, I am damned glad to have an Iowa, in any system VaS or CD of Battle Stations.
With respect to RN battleships, I discount the Vanguard, because ultimately she was not commissioned until 1946, after the war ended. She was a very capable ship, but was not exactly a WWII ship. Undoubtably she was very sea worthy, but she was undergunned relative to state of the art in 1945, at least in my opinion-her guns were from the same design that had appeared orginally on the Queen Elizabeth class in like 1915.
The KGV was a modern battleship in 1941, but was less so by 1945. Still it was a fine all around class of ship, despite not being the super weapon the Admiralty wanted it to be in December 1941-this is the lesson of Prince of Wales.
The US Navy, on the other hand, expanded rapidly adding, two new classes of battleships after the commencement of the war. It went from a fleet of 6 carriers to a fleet of over 20 Fleet carriers and a huge number of escort carriers. While the RN did have a large increase in the number of escort Carriers (many of which were built by the US and given to the RN), the RN never deployed fleet carriers at the same levels the US did, it simply did not build that many, and a good portion of the RN carriers were pre-war designs.
None of this takes away from the bravery, courage and capabilites of RN crews and ships. RN crews were top notch and her vessles were solid. Frankly I think the assumption that a US or Japanese fleet would automatically loose to a US fleet is sort of preposterous. There might be small differences in quality at the top end, but the biggest mistake you can make is to think you have the game locked because you brought a Yamato and your opponent only borught a KG V, or a Bismark or a Littorio, or a Richelieu.