Alright I'll actually put some effort in.
Hop is fine. The problem with Hop is there's just too. Much. Hop.
Maybe the actual total was less than it felt while I was playing but it seriously was like every time I saw the guy I had to brace myself for a battle. Fighting Blue or Silver felt like an event when it happened because they only came up at a few points over the course of the adventure, and every time you could tell they had grown just as much as you had. Hop's actually your friend unlike those two so it makes sense that you'd touch base with one another more often. But not every single one of those times needs to be a battle, especially since it barely feels like he's advanced for so many of them.
The frequency of his battles is made worse by the fact that he keeps commenting on like every other attack. He quips when he crits, when he super effectives, when you crit and super effective, etc. I don't think that's meant to be a tutorializing thing so much as a "wow, look at how reactive this NPC is, isn't he cute" kinda thing. But it's just too much. One or two comments during the general course of battle, as the tide shifts from you winning to him winning to a close victory/loss etc, would be fine. The fact that Leon acts the same way during the literal final battle is definitely supposed to be endearing and evocative of those fights with his younger brother, but it comes off as annoying for the same reason I think Raihan's annoying for talking about the weather whenever he uses a move that changes it.
His actual character arc is good. I mean, he actually gets one that feels natural and earned so that's more than I can say for the rest of the cast.