>>34078138Make the Trainers smart, and give them movesets that are reasonable for the point of the game they're faced. In FRLG, Brock has two Pokemon, a Brock and an Onix. As his Geodude is Level 11, it could reasonably know Tackle, Defense Curl, Mud Sport, and Rock Throw, but it only has the first two. It would be acceptable to let it have all four moves, but it shouldn't have Magnitude because it doesn't learn that until 16, and it shouldn't have, say, Brick Break because that TM isn't available until the S.S. Anne at the badge's city. His Onix could reasonably know Tackle, Screech, Bind, and Rock Throw, but only knows Tackle, bind, and Rock Tomb. Rock Tomb is the TM he gives, so it makes sense for its moveset. Giving it Dig would not be fine, because it's an 60 BP move with an invulnerability turn and you won't get it until Cerulean City.
Some may feel Brock having only two Pokemon is too easy, but you have to consider first of all that he's the first Gym Battle in the game, and the player doesn't have that many options available to them at that point in the game. That said, letting him have a third Pokemon probably would be fine; giving him SIX however is not.
It's about balance, not stacking a bunch of nonsense in the AI's favor and intentionally gimping the player at every turn, which is precisely what Reborn does.