There are some small things in the story to have an opinion about that appear in some chapter. The simplest and an early example would be Jenny and Joys not being able to tell the difference between each other. It woud have helped world building while giving character to the Jennys and Joys if they could. (Its only a single sentence in one chapter)

But there are some others more relevant: like the lack of descriptions. Or that the MC is shown as the most competent, which is actually fine since its in a way that does not diminish other characters. There also hasen't been anything that's explained why fights happen as if it is in a game, why do pokemon have health, why do they faint. There is also nothing that explains what makes a competent trainer, maybe because they have better Pokémon? But that would stale, or maybe there is a reason that makes competence have no issue beyond the basics?

Things, details that gets attention but nothing that is a fault or problem. If one does not get caught on it at least 

But there is only one thing that actually needs fixing. With me being really nitpicking.

 It is that time passing is sometimes brough upp weirdly. For example. It is written that for the next two hours they'd did this, then it is write That after another two hours past they moved on. Basically bringing up that the same two hours passed twice times or more. Happens sort of often which is why I bring it up.