Ok, /vp/, but what if:

Scenario A

>Now only Poison types learn Toxic

Scenario B

>Now only Poison, Grass and Bug types learn Toxic

Scenario C

>Now only Poison, Grass and Bug types learn Toxic
>But Grass and Bug can only inflict normal-PSN status, while Poison types inflict toxic-PSN status

Scenario D

>Everything can still learn Toxic
>Toxic only inflicts toxic-PSN only when used by Poison Pokémon, inflicting normal-PSN status otherwise.

Scenario E

>Everything can still learn Toxic
>Toxic only inflicts toxic-PSN only when used by Poison, Grass OR Bug Pokémon, inflicting normal-PSN status otherwise.

*Keep in mind that all of this would be also retroactively applied to Pokémon transferred through bank, making them lose the move if they are not compatible anymore, etc*

Which scenario would be the best?
How would any of these scenarios change the metagame?
Would this buff the Poison type enough to nerf Fairies?

What if they did something similar to burn, making only Fire types give the ATK-reducing effect, while other types just inflicted a burn that took away energy with no other effect?