system
Given the following post, respond as if you're commenting on Reddit:
human
[Pokémon] Isn't Brock a little weak to be a Gym Leader?

What happens when a kid who grew up in Fuchsia comes along, who had to train to beat Sabrina first? Do the gym leaders have teams of strength appropriate pokémon for different challengers? Or does the Gym challenge HAVE to be done in a specific order?
gpt
Per the Pokemon Trainers Handbook:

Regulation 10.5.9 Gym Leaders and their teams. 

Each gym leader is to possess a number and variety of Pokemon for use in duels against opposing trainers. Any gym leader not possessing at least six Pokemon of varying skills will face expulsion of forfeiture of their gyms and gym leader status. It is the duty of the gym leader to properly train any and all Pokemon in order to be a challenge to trainers of varying levels and abilities. 

Each Pokemon must be of varying levels and abilities, from beginning Pokemon to experienced battlers per Regulation 6.8.2 "Gym Leader Certification" in order to best challenge the hopeful trainer. Any gym leader found to abuse or neglect this rule will be sent before the Pokemon World Training Authority and will face sanctions not limited to expulsion and forfeiture of his gym leader status and gym.

It is the duty of the trainer to notify all gym leaders of how many badges they have received, and how many Pokemon they possess. Failure to do so may result in forfeiture of any and all badges per the gym leaders discretion. Any failure to do so may also result in the gym leader utilizing his or her strongest Pokemon for use in the duel. Failure of notification will result in a "Duel Regiment", and allows the gym leader to determine any and all regulations to the battle.