Ash winning the championship felt sour. The end of his final fight against Leon was emotional thanks to Pikachu and the mons, but the rest of the fight was very dull. The world title had no impact on him, the next day he was with Goh as if nothing happened. Nothing happens.
Maybe if Ash didn't get the championship, a deeper message could be given about how valuable his bonds with people and pokemon were throughout his journey, that which made him grow as a person. Having come so close to the world championship didn't feel so bad when he won so many things that are going to be with him for the rest of his life.