…how will that work on pokemons that are already caught?
To address the implementation of Natures highlighted by this 7-year old post:
Incorporating Natures adds a new element which can influence the value of Pokémon. While it should be random upon release, one issue to discuss is what to do will all these Hardy-natured Mons. Allow a one-time change like we can with Abilities? Seems a bit wild from both the PvP and trading perspective. My initial thoughts were to keep the current Mons as Hardy upon the future release of randomized Natures.
While Natures have their nice benefits when it synergizes with the Mon, I see a whole lot of potential for a displeased trainers. E.g Find a 20+ IV, max Speed Bagon. Woo! And then you notice it’s a bit Sassy with increased Special Defense and reduced Speed. Without breeding, Natures are a real toss up and while I wouldn’t personally mind the randomness, future-AK can hear the disgruntled cries of the “I’m-so-unlucky ones.”
And to quote Rigaudon in
"Ownership and Abilities" (2017) from a long while ago:
and we will not let you change natures no matter how much it is asked for or insisted upon
Not sure if those sentiments are still held by current Staff, but Rigaudon goes on to talk about breeding and ruining "perfect" Pokémon.