One thing that may (and I emphasize may) be crippling polularity the WWi era ships in small/fast gun is the unit system. In the Big Gun system, where you can arm whatever you want over 3" (including secondaries)
Many of these "bitty boats" bristle with cannon over 3", It might be easier to arm the casemates than mains in some, not so in others. Also the relative speeds (Big Gun gives a minimum allowable of 25 knots, and speed is basically 0.1ikm/h per knot) are a bit closer. And pumping is related to displacement, not a substiturt for guns.
One reason for thet strong may, I understand some of the WWi era ships, like VU and Espana have been pretty popular in small/fast gun from time to time.
Of course one of the reasons for the popularity of bigger WWII ships in Big Gun is more room for stuff in side, especially for a novice builder. An Espana is a challenging build in Big Gun if you are arming the mains with turrets. I believe Jeff is currently rebuilding his with fixed mains. Of copurse, there is that whole displacement thing......
Cheers,