Name a bigger downgrade than this.

This. I 100% agree with you. XY was a huge disappointment compared to Gen V and was a enormous downgrade. ORAS was a step in the right direction, but it still paled compared to Gen V. I mean, we went from well-developed characters, great story-telling, an actually threatening villain team, and great lore, right back into an idiot plot, flat characters (and that's the nicest thing you can say about them), laughable villains, and story/lore that was contradicted at every turn. That first step from Gen V to Gen VI was a dozy of a drop, and it hurt.