We don't need another 25 years long series.
I'm sure the anime wont come to that resolution of continuing a specific story for 25 years, but I do speculate that it will keep up the tradition that its protagonist journey never ends.
With that said, I again hope the pokemon anime incorporates some innovative ideas to further increase its target audience engagement in its next story.
I fathom the idea of the anime hosting a fan poll, that allows its children audience to select / vote a non-legendary / mythical pokemon they would like for the new protagonist to catch during a special / filler episode. The pokemon could be the protagonist's 7th pokemon, which could later be released or stored if the writers think its purpose in the story will be shortly limited.
I understand the writers have their selection of pokemon outlined for its protagonist, however I think audience participation in this activity could be interesting.
I think the last I can recall the anime experimenting-around with
Pokemon roulette for developing Ash's team was in the first season when introducing Butterfree, Raticate, Haunter, and Primeape. They didn't stay long and I think the concept of their introduction was to see if they fit. I can even recall the Black and White anime adventure retrofitting the Pokemon roulette concept.
However, Pokemon Journey's was the zenith of the Pokemon roulette concept when Goh was introduced in my opinion.