>>26471386Every game up to gen 5 gave you some freedom in what order you beat the gyms in.
Gen 1 let you battle Surge, Erika, Koga and Sabrina in any order, Blaine can be beaten any time after you beat Koga and can use Surf.
Gen 2 let you face Chuck, Jasmine and Pryce in any order. The Kanto gym leaders can also be beaten in any order.
Gen 3 let you skip Brawly and Winona until you reach the Pokemon League.
Gen 4 let you battle Fantina, Maylene and Wake in any order in Diamond and Pearl. I think Platinum may have forced you to beat Fantina third, I can't remember if it was compulsory.