I don't know how many times I will have to say it:
Pikachu is the real star of Pokemon, both anime and games, so they are not going to get rid of the Pikachu we have met for so many years. And since they are not going to trade Pikachu to another trainer, Ash is not going to leave either.
Besides, there are several things Ash should do in the anime before we even consider him officially elaving the anime:
- A rematch against Giovanni, leader of Team Rocket.
- Winning the Kanto's League, to compensate the disaster of the very first season.
- Ash challeging the Elite Four and becoming Kanto's champion, just like in the games.
- Finally, if Goh actually catches Mew, then Ash will have to battle and capture Mewtwo.
If Ash is removed before these events happen, then people will lose interest. Besides, they said that Ash will always have 10 years in the anime, so there's no reason to change him.
One more thing, is the next region is based on Spain, I don't want Ash leaving the anime before he visits my homeland.