The delay for the KGV is iirc two fold.
1. Turret issues, a shift from three treble 15 inch guns to two quads and a twin 14 inch gun. This led to a delay of few months.
2. Shifting of manpower to other causes (corvettes merchant ships war time repairs etc).
Fixing item 1 but leaving item 2 might be a more realistic option.
However if fix everything and have all five in service I would imagine that the numbers game would have led to the Germans not sortieing with Bismarck and instead we would end up with Bismarck spending the rest of the war hiding off the coast of Norway with Tirpitz.
I largely agree.
If the British hadn't interfered, the 2nd WNT would have allowed capital ships to have 16" guns, instead of reducing the maximum calibre to 14". Therefore, the POD could be that the British don't have the new treaty reduce the maximum calibre.
However, another POD could be to bring the decisions to change to twelve 14" and then ten 14" forward by a year.
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And re the discussion on the Illustrious and Implacable classes. The WNT and 1st LNT allowed aircraft carriers to displace up to 27,000 tons. It was the British who had it reduced to 23,000 tons by the 2nd LNT (and they wanted 22,000 tons, which is why Ark Royal displaced 22,000 tons).
However, instead of adding a second full length hangar to the first 3 and making the lower hangar full length on the second 3, I think they should have used the extra 4,000 tons to increase the height of the hangar(s) from 14 feet and 16 feet to a uniform 17.5 feet. If there was any displacement after that I would increase the width of the hangars from 62 feet to 65 feet.