Smaller Japanese battleships could strengthen the whole fleet

Would Japanese treaty battleships be more effective than the Yamato class?

As part of the whole fleet, possibly: fast 16-inch ships could free resources for more carriers and cruisers and create a more flexible force.

Fast Japanese battleships with 16-inch guns could prove more useful than the Yamato programme, depending on how many were built. Smaller capital ships could place less strain on the production system. That could allow completion of additional cruisers and carriers that Japan did not finish while building Yamato-class ships. The possible advantage lies in a more flexible overall fleet.