PnP rules allow one long rests and two short rests every 24 hours (you can rest more but gain no further benefit). Class balance is based on ratio of two short rests for every long rest. I.e. it shouldn't be 1, it shouldn't be 3, it should be 2 short rests per long rest.
2 short rests means that WLK will be able to cast 6 spells per long rest which would put their spell usage on par with wizard. You are right.
