Well, I definitely don't agree with the subsequent banning of all good swift swimmers until all we have left are lumineon and luvdisc, but I don't think we'd need to go that far if only a few swift swimmers show themselves to be too good.
I can see the differences between 8 turn rain and infinite rain, but perhaps I am just underestimating or simply not seeing how rain is easily stalled out of eight turns. Was nothing in UU not capable of doing this since Damp Rock was apparently considered suspect at one point? Was it too hard for UU pokes to last those eight turns whereas OU exclusively contained pokemon who could handle 4th gen rain teams with ease? And even under the rain, don't most swift swimmers still need to use a turn to set up anyway (kabutops needs his sword's dance, gorebyss needs his shell smash)?
As far as rain stall goes, it's a very real strategy, even if it isn't used. But I'm not going to argue for losing the playstyle too much. When 4th gen salamence was banned, all teams using the fatmence build had to drop him. All variants of garchomp also had to go once his broken set was found. It might be a bit too complicated to ban the combination of swift swim on select pokes (rain stall still uses swift swimmers) and drizzle, so if drizzle is found broken then losing rain stall will just be something we have to deal with unfortunately.