The professor is a young prodigy, but prefers hands-on research. As a result of unexpected events leading to your first pokemon partner, he suggests a race to complete the Pokedex of the region. He journeys with you, doing research on pokemon as he goes along, and often battles with you to see the differences in how you both raise your party. His team constantly changes, and is hard coded to have random pokemon every battle; you can't prepare too far ahead against him since you won't know what he'll have. Kukui was a step in the right direction with how he wasn't afraid to travel around with you and the others, but he only ever fought you once. Imagine Kukui randomly fighting you to test out new moves and see how you react to them, like an actual rival battle that happens when you least expect it.
That's my ideal next-gen professor; a character that journeys with you and actively fights you to compare data. You're not the only important character with a Pokedex anymore.
