I think they would have been better off letting go of Ash, and start with a new Protagonist. The new Ash looks and acts nothing like the old one, or atleast he didn't appear to act the same from what I can remember from the decade or so it's been since I cared for the anime at all. This one seems to have been knocked down a few IQ levels, something that is hard to do considering how thick Ash could be.
Ash is based on Red, and in Sun and Moon we see him in his teen years, something the studio could have taken advantage of and move to a new lead without the restrictions the old one has on hims being a old character with set behaviour patterns.
In fact they could have made Millions by giving Ash a Send off arc ending with a movie, the same way that sun and moon broke sales records for the game by reintroducing aloha versions of the original generation, and having Red and Blue turn up with cameo's. They could have sold so many movie tickets having Ash finally achieving his goal of being a Pokemon master, and at the end they could have meet the new kid and have him give a descendant of Pikachu to him because like Ash he or she was late and the Pokemon had already been distributed. Yu-Gi-Oh did something similar and it worked well, the baton was passed on to the new generation.
I would have gone to watch that movie, or atleast bought it on Blu Ray. they really missed their chance.