>>41427861>>41427840All five regions do gate keep to some degree, Kanto does it overall the least you have to do Brock first, Misty second, you need to do Koga before Blaine and Giovanni is always last, so you have quite a lot of control over how the mid-game plays out.
In Johto you are required to do the first four gyms in order, you need Falkner to get past Miracle Seed Man, Bugsy for Cut, Whitney for Sudowoodo and Morty for Surf, from there you can do Chuck, Jasmine and Pryce in any order and you do Clair last.
Hoenn (in RSE) requires you do Roxanne first, you need to beat Wattson to take on Flannery and you need to defeat her and Brawly to fight Norman so you've got some variety with where you battle Brawly, from there you can skip Winona until the very last gym of the game but you do have to do Tate & Liza before Wallace/Juan. So the variety comes down to when you do Brawly and Winona's battles.
Sinnoh's first two and last three gym leaders have to be done in that order, in DP and Pt you have to battle Fantina in her designated gym spot (5 or 3 respectively) however, iirc you can battle Maylene or Crasher Wake in either order (this was definitely the case in DP can't remember if it was in Pt)
Unova is (unless I'm mistaken about Platinum) the first games to completely railroad the player to do the gyms in order, in BW there is always something blocking the player from progressing and that's continued in B2W2.
