The Dreadnought really put to rest the "moderate dimensions" theory. The 1894 Brassey's The Naval Annual makes the case for moderate dimensions. I have written about this before, but perhaps I have a new perspective. The argument is that in the age of sail, they didn't build all 100 gun ships. Instead, the majority of battleships were 74's. That is the crux of the argument. The problem is that from the 1880's on, smaller ships had thinner armor and smaller guns. With the coming of the Dreadnought, the disparities had become so great that everyone could see the uselessness of building smaller battleships. It also eventually killed off the conventional coast defense battleship. There was still a place for monitors of the sort used in the war, but they were not intended to fight other ships. They were strictly for shore bombardment, for which they were a reasonable solution.
Another solution to moderate dimensions is to use armored cruisers in the line of battle. That was done by the Japanese in 1904 to 1905 out of necessity. They had loss two battleships to mines, and all they had to give their battlefleet numbers were armored cruisers. Most only had 8in guns, so they were much less capable than ships with 12in guns. That was not really a viable solution, either. It was a measure only made reasonable by the poor performance of the Russians.