Once.Question: Has there ever been a time when all Pokemon from a banlist were reintroduced into the tier they were banned from? For example, all of UUBL being allowed into UU after the meta had developed beyond the time the Pokemon were banned.
Would that even be feasible?
This was back in Gen 4 and when it was current gen. Prior to, Pokemon were simply placed in [UU]BL if they felt too powerful. Once UU was more recognized as a tier, the [UU]BL Pokemon were introduced into the tier and then banned appropriately if they were too powerful.
This was a lot more due to a cultural / tiering change at the time.
In Gen 5 this was also done, sort of, for all non-box legendary Pokemon into OU. Long story short - clusterfuck of a mess. Imagine a tier where you could lead Deoxys-S into NP Darkrai. Not good times.