I like the idea of his arc culminating in the realization that becoming the champion isn't truly his dream, but I kinda dislike that he became a Pokemon researcher. That's already happened with Bianca, Gary in the anime, Brendan/May sorta (they were researchers from the beginning, but after your last battle in the story they declare their intent to go back to Littleroot to focus more on it)...it's just starting to seem like the writers just default to this when they don't know what to do with a rival character.
If I had to stick with the Pokemon-researcher thing, though, I'd still change it up a bit. One, I'd have him actually show an interest in science and knowledge throughout the story - that would've been such an endearing character trait, omg - and two, instead of having him become full-fledged professor Sonia's apprentice, I'd have Sonia give up Pokemon research for something else, maybe even getting back into the Gym Challenge, and Hop take her position. Seriously, she had so much dialogue where she seemed like she just hated her job - it really seemed like the story was flowing towards her having a similar arc to Hop, realizing that she has a different dream than what she's expected to do because of her family, but then they just never did anything with it.