I don't think letting people choose between ties is a good idea, since it would probably lead to a significantly larger banlist (Mew, Manaphy, etc would be very broken if they could double their attacking stat of choice rather than speed).Unnatural
Metagame Premise: If a Pokemon uses a Nature where their highest non-HP stat is lowered and their smallest non-HP stat is raised, the stat being raised gets Doubled instead.
Example:
Kingambit’s highest non-HP stat is Atk and it’s lowest non-HP stat is Spe.
With 252 Spe EVs and Neutral Nature, Kingambit would have 199 Speed.
With 252 Spe EVs and Jolly, Kingambit would have 218 Speed.
However, with With 252 Spe EVs and Timid, Kingambit would have 398 Speed instead.
Kingdra is a good example to show off what happens with certain stat distributions.
Kingdra’s lowest stat is actually HP, but in this Meta, Speed is the lowest non-HP stat and will be the stat that can be doubled.
Kingdra’s highest stat is tied between Atk, Def, SpA, and SpD. In this case, the highest stat will follow similar rule to Beast Boost/Paradox abilities where it’s prioritized as Atk > Def > SpA > SpD > Spe. In this case, for Kingdra to get x2 Spe, it needs a Timid nature. In cases where the lowest stat ties, it goes in reverse order where Speed is treated the lowest.
Potential Threats and Bans:
Kingdra has a very good stat spread for a Metagame like this. Kingdra won’t miss its Atk stat that much as it has stronger special options anyways and under Rain can have 1,076 Speed (269 * 2 * 2)
Azumarill’s Speed stat being its lowest stat means it can have double Atk with Huge Power and double Speed with a Hasty nature. While Adamant would be stronger, having same Atk and Spe and fully invested Great Tusk Atk is pretty solid.
Great Tusk gets the benefits of both worlds. It can have a regular set with Adamant or Impish or Jolly natures and do just fine, but additionally Great Tusk can run Calm sets to double its SpD up to 410. So Great Tusk can run regular sets, and additionally run a Specially Defensive set that greatly increases your SpD.
Questions:
1. I added the priority list for ties to simplify what happens, but would it be better to let people choose between ties? Like for example instead of just timid Kingdra you could also have Jolly Kingdra doubling the speed stat since SpA is also Kingdra’s highest stat too.
2. In some cases of mid-battle form changes, some Pokemon’s highest anf lowest stats change distribution. For example Eiscue‘s highest stat is Def and lowest stat is Speed, meanwhile Eiscue-noice’s highest stat is Speed and its lowest stat is SpD. Should Hasty still double Speed after changing form, or should the nature only provide a +10% bonus to speed like it normally would?
3. Changing the nature bonus from +10% to +100% sounds most natural (ironically) but feel free to say how much you think it be a higher bonus or a lower bonus.
Moltres-Galar is probably broken, since it can spam Brave Birds off of 538 attack. Zapdos-Galar also gets 538 special attack, but it only learns 5 special moves (Ancient Power, Hurricane, Tera Blast, Hyper Beam, and Swift), and none of them is an accurate STAB move.