Swift Swim Ban
Despite the far from unanimous decision to ban swift swim, most players now feel that it was the best option. Reasoning for Swift Swim ban and rain suspect below.
Suspect Reasoning: The biggest problem with rain is that there's almost no opportunity cost to using it. Seven turns of Pokemon that already have tremendously boosted stats also having doubled Speed and a boosted STAB is insane. I know we all know this, but actually spelling it out really puts into perspective just how incredible rain is. On top of the incredible power and Speed of Swift Swim users, Politoed itself gets massive boosts to its stats, which makes dealing with rain all that more difficult. It is perfectly reasonable for Politoed itself to outlast the rest of the team, which means there's pretty much a constant source of rain that doesn't require wasting a turn, but merely a slight shift in momentum that is more than recovered when you get to bring out Kabutops, Ludicolo, Omastar, Kingdra, etc.
Swift Swim is banned from Tier Shift. The council voted with two in favor of banning Drizzle, two in favor of banning Swift Swim, and one in favor of banning Damp Rock. A tie-breaker vote was in favor of Swift Swim over Drizzle. The whole council agreed that rain needed to be nerfed in some way but not everyone agreed on how much. Drizzle was less of a nerf than the others that forces alternative rain setters that have to take hits to set up rain and cannot take advantage of a free switch not to waste a turn of rain. However, this was felt to not be enough of a nerf by some that chose to ban Swift Swim instead. The playstyle rain has the most advantage against is offense, precisely because of Swift Swim. Taking that particular ability made sure rain was not overpowered, however it does severely reduce the viability of rain and may stop it from being used at all at the highest levels. Banning Damp Rock would have also nerfed rain plenty but most felt that Swift Swim was a better option overall.
Suspect Reasoning: The biggest problem with rain is that there's almost no opportunity cost to using it. Seven turns of Pokemon that already have tremendously boosted stats also having doubled Speed and a boosted STAB is insane. I know we all know this, but actually spelling it out really puts into perspective just how incredible rain is. On top of the incredible power and Speed of Swift Swim users, Politoed itself gets massive boosts to its stats, which makes dealing with rain all that more difficult. It is perfectly reasonable for Politoed itself to outlast the rest of the team, which means there's pretty much a constant source of rain that doesn't require wasting a turn, but merely a slight shift in momentum that is more than recovered when you get to bring out Kabutops, Ludicolo, Omastar, Kingdra, etc.
Swift Swim is banned from Tier Shift. The council voted with two in favor of banning Drizzle, two in favor of banning Swift Swim, and one in favor of banning Damp Rock. A tie-breaker vote was in favor of Swift Swim over Drizzle. The whole council agreed that rain needed to be nerfed in some way but not everyone agreed on how much. Drizzle was less of a nerf than the others that forces alternative rain setters that have to take hits to set up rain and cannot take advantage of a free switch not to waste a turn of rain. However, this was felt to not be enough of a nerf by some that chose to ban Swift Swim instead. The playstyle rain has the most advantage against is offense, precisely because of Swift Swim. Taking that particular ability made sure rain was not overpowered, however it does severely reduce the viability of rain and may stop it from being used at all at the highest levels. Banning Damp Rock would have also nerfed rain plenty but most felt that Swift Swim was a better option overall.