>>46867376all gym leader battles should be three pokemon, because in my head canon I imagine they are extremely strong trainers who were elected/chosen/hired to be the pokemon league representative in a selected administrative region
so they would have lots of prize money, be viable to apply for the Elite Four, and and have multiple pokemon at the ready, that being said they know to get a badge trainers may be at many different stages of their journey
with all that in mind, Pokemon League rules would then stipulate that obtaining a League Badge would require beating a gym leader 3v3 (half of what an Elite Four member *should* be)
rate and subscribe to my autism