It had a small dex, and WAY too many legendaries and ultra beasts, and in case I need to make this clear, Alolan forms don't count as new pokemon.
However the new pokemon it did have outside of those categories were pretty good, with the exception of a few designs.
Here's how it could've been made much better
>more new pokemon, less legendaries
>if 10% of all pokemon are legendaries, they don't feel very legendary
>a lot of the ultra beasts are unnecessary, and might as well be called legendaries
>concentrate more on the alien, weird aspect of the ultra beasts, and don't set out to create a rare, legendary pokemon under a new title, but rather more pokemon like nihilego or poipole (how the fuck is poipole the only ultra beast that can evolve?)
>some of the ultra beasts are really cool and interesting, but I can't help but think that the time spent on designing these pokemon that are only ever going to be available in the post-game had been spent on designing something that actually brings more depth to the region, the dex could've been better
>regional forms is a cool idea, but the fact that they went out of their way to only have alolan forms of kantomons is near insulting
>diversify your alolan forms, maybe remove a couple existing ones