The following is a newly-translated blurb from Takeshi Shudo, the man behind the Pokemon anime. This blurb was posted many years ago, but never translated. It seems to pertain to Shudo's potential idea for an end of the anime series.
Months and years having passed, Satoshi, who has become an old man, suddenly remembers the old days. It is an embellished memory of childhood. A fantasy...The imaginary creatures, Pokémon, and their adventure. Friendship. Coexistence. That is, in the real human world, something Satoshi could not possibly encounter. However, somewhere in childhood, surely Pikachu and the other Pokémon are there, Musashi and Kojirou are there, Mewtwo is there...
Not just that; everyone Satoshi encountered on his childhood adventure can be seen in the elderly Satoshi's eyes. Satoshi hears his mother's voice in his ear. "Come along, hurry to bed. You set off on your journey in the morning, don't you?" The next morning, woken up by his mother, Satoshi, once again in the form of a young boy, energetically rushes out of the house.
This is a search "Not to catch Pokémon, not a journey to become a Pokémon Master, but to discover what I am", a journey with the goal of coexisting with others.
Long story short, Mr. Shudo seemed to desire an ending where Ash's journey was nothing but a dream. I don't know about you, but I really don't care for the ending! I guess one day we'll see if those in charge of the anime now decide to take that direction! Thanks to TheDreamingHawk for the heads up!