>>32815326That's because there were so damn many of them that there wasn't enough screen time to get them any real development. He caught NINE different mons in Unova, and with Pikachu constantly being around he could only have five of them with him at a time. And that dropped to four in the final season when he brought Charizard back.
In past seasons, he only had Pikachu+5 or 6 others, so there was plenty of screen time to go around.
