Honestly the formula and Ash really aren't that bad, and they're pretty suitable for the franchise. The real problem is Team Rocket who are used way too much, are way too ineffectual, and generally try to hard to be both villains and comic relief leading them to fail at bothThe anime just needs some god damn progression.
I think most folks, including kids, may indeed be getting tired of this formula where it's Ash, getting badges, cherry-picks Pokemon as opposed to catching them all (like he was supposed to be doing...), reaching the league, losing said league, restart with another group of folks, almost never carrying over from a previous region, etc.
It's so overdone.
Ash needs to age, he needs to get back that thirst for filling that thing called a Pokedex, he needs to WIN leagues. Finish his story and pass the torch to another, or at least bring back fan fav characters and don't toss them in the garbage every time the region finishes.
And STOP releasing Pokemon that actually have a personality and are good. :/
And remember you have a god damn Pidgeot, who I swear by now is just plain miserable and lost his mind after being abandoned for nearly two decades with a broken promise of being seen again.