The mainline Pokemon games follow the same traditional storyline with only a slight deviation depending on the threat that the region is facing. It makes sense that The Pokemon Company wouldn’t want to mess with a formula that works, but it does get a little stale. Especially when the story continually focuses on you, the player trainer, and your ability to beat everyone and become champion yet again.
Yet, it’s not that there is anything overtly wrong with the player trainer overcoming the game’s obstacles and becoming victorious. But, in prior games outside of this, there was little character development beyond it. Sure, the player trainer did beat clarity into N, but it was the conclusion and didn’t ultimately matter.