I feel like Pokemon Champions is somewhat a reply to the dexit negativity and is overall a good thing
From recent titles in the pokemon franchise starting from sword and shield, we've known that dexit is more or less inevitable with the ever rising population of new pokemon in each game. I, for one am not affected much by it considering I tend to use the said new pokemon of each new region.
That being said, I have a strong feeling that Pokemon Champions will finally be a switch release where trainers are capable of using their past pokemon along with every other new upcoming Pokemon so trainers won't have to be limited to the choices each region has. Granted, it's not the same feeling as using an unavailable favorite pokemon on your journey through the story, but idk.