Honestly, significant bosses like team leaders ought to be using 4 Pokemon minimum by the time things are level 30. Emerald's Watson's Pokemon are levels 20-24, and he has 4 of them. Having only 2 (and a Golbat and Ariados at that) at 30 is a disgrace.
Right? There's that one admin in Alpha Sapphire that literally only has a Sharpedo. Like wat.