But still, Ash might soon become the strongest trainer in the world thus limiting what they can do with him without rebooting everything.
To be the strongest trainer, he must meet again with Alain, Tobias and all the other league champions. Here is the definition of the pokemon master in the anime.
How many pokemon masters can you have? What is the pokemon master? What is the meaning of the anime if the anime ends or the lead role changes without getting the answers to these questions?
I still do not understand the league difference with the World Coronation Series. This also needs to be clarified.