The biggest reason I hate SM is that it's nothing like the games. For all the grief I give Black&White, at least it tried to stick to the games. In Sun and Moon, Kiawe, Mallow, Lana and Sophocles are not Trial Captains wherein they would challenge Ash prior to him challenging the Kahuna for the Grand Trial. As a reward for completing said Trials, they'd reward Ash with Z-Crystals and/or the honor of battling them. Outside of Kiawe(and to a lesser degree Lana), none of them even battle and without them being Trial Captains, their purpose in the series is pretty much removed. When Ash got the Electrium-Z, Sophocles role was removed. Ash got Grassium-Z on Akala so Mallow is a pointless character. Ash hasn't gotten the Fire one but that's because Kiawe has it(same with Lana and Water). In other words, Lillie is the only character with a purpose and even her role is not that well defined. Her fear arc lasted far too long and since it ended, what's her goal/objective within the series? Alola Guardian? If so, this isn't Voltron/Power Rangers....
I mean in XY, Clemont's role was as an obstacle for Ash and was on the journey to gain more self-confidence. Bonnie was there for comedy relief and Serena's role wasn't fleshed out until 38 Episodes in(took far too long). Even then, she had a crush on Ash so she at least had a reason to be there. What darn reason do the SM cast have other than going to a school that has been proven multiple times not to be necessary in the Pokemon universe(at least for Ash).