>>32863350It started in BW as a clever addition to the rival formula: Cheren and Bianca are both friends with different but understandable goals. Then N acts as the real rival, but you face off against all 3 throughout the story, and they each have their own conclusions to their stories. Interestingly enough, BW2 was the last game to really preserve the rival dynamic of Pokémon, with naming the rival and all that, and was more traditional with the whole approach.
XY was where things went to shit. Instead of a rival battling you for superiority throughout the story, there's Serena, Tierno, Shauna, and Trevor. The latter 3's motivations are very weak, and none of them really need to become stronger to accomplish their goals.
I would like to see Tierno return as a seasoned warrior in USUM, using Oricorio, though. Serena sucked too, I don't even remember her motivation, but at least she tried to put up a fight.
ORAS wasn't much better. Hoenn's rivals are weak too, especially Wally, but at least he managed to become really strong in the end, though before he gets Mega Gallade the fights with him aren't all that interesting.
Then Sun and Moon gave us Hau and Gladion. If it had only given us those two things would probably be a lot better. Lillie is just way too much, with her constant cut scenes and family feud. She overshadows the main character.