pokemon vs pokemon-form vs pokemon-variety

Hi all, something has been on my mind a bit and now has drawn to a head with some updates to the evolution-requirements, where we now have required_pokemon_form pointing to a pokemon-form rather than a specific pokemon. I think there is now a bit of a disconnect between pokemon-varieties and pokemon-forms.

For example, take an evolution with a pokemon variety e.g., rattata-alola, evolution-chain/7. This used to point to the Pokémon at pokemon/10091, but now instead to pokemon-form/10193/. A Pokémon form "belongs" to at most 1 Pokémon (i.e., a 1-to-many relationship), and the only difference being that a form might have some minor field differences (just like a variety might).

I understand that maybe pokemon-form differs from pokemon-variety as it is purely cosmetic rather than a new Pokémon (moves, types etc), but I think it is creating unnecessary complexity when we could just add a new pokemon (which would still be different e.g., sprites).

We have a bunch of duplicated data, e.g., pokemon-form/10193/ copies most of the fields from pokemon/10091. This creates a multitude of problems e.g.,:

Let's assume we want to grab the types (normal/fire/water) of rattata-alola, where exactly should we look now?

It is pretty obfuscated as to which form/variety fields should be taken as ground truth.

I can't think of a case where a pokemon-form would not have any fields changed that could not be represented in a Pokémon. The monotonous part is then copying across these fields to pokemon (e.g., is_mega).

I really think that there is justification in merging pokemon-form with pokemon (just as varieties already does).

Please correct me if I'm overlooking something, but I really think each pokemon-form should be a pokemon, just as pokemon-variety already does (i.e., a pokemon-form/... just points to a new entry in pokemon/....). And, we dont need pokemon-form relation AT ALL.

Start by comparing the pokemon/10091, pokemon-form/10193, rattata-alola, and evolution-chain/7 resources described in the issue. Trace which fields are currently authoritative for a variety and form, then document the model changes needed to remove duplicated data. Done means the relationship is unambiguous and the affected API resources remain consistent.