That's cool, but I kinda take issue with difficulty hacks as a concept. This is by no means an attack on you; go wild and have fun hacking! But as you make a difficulty hack, bear in mind the resources you'll make available to the player.
Pokémon games generally don't give much thought to the competitive side of things, until the postgame. That's when the player has access to all the possible TMs, training facilities, more money for vitamins/Power Items, etc.
So, taking your Roxanne/Brock team for an example: yes, it's a lot cooler than a few Geodudes and an Onix/Nosepass, but more importantly: how will the player be equipped to counter this team at this point in the game? Will they be able to selectively manage their EVs from the get-go, or will they be ruined by levelling up against Metapods/etc?
The team has some serious stall action going with some pretty solid movesets for that early in the game, too. Rock Slide/Heavy Slam/Dragon Tail by the first gym - no joke.
There's difficult, but then there's infeasible/tedious/impossible. Is the Player going to be taking on this gym with your average Squirtle/Mankey/Pidgey team, or will they have some more colourful options, like the gym leaders have? I just have visions of rocking up with a Squirtle with Tackle/Withdraw/Bubble/Water Gun, and then being smacked with a Dragon Tail. 😅 It just doesn't coalesce unless it goes both ways.
