The bolded solution is probably the best, but you're right on the floodgates point sadly.... :/
Jukain
I just wanted to tell you that I agree with you that I do agree that Baton Pass is pretty broken. However, I think it would be better to not murder the playstyle completely, at least not right away - in the vein of Drizzle not being banned on its own in Gen V, but rather DrizzleSwim and Thundurus/Tornadus-Therian were banned - if we can find a similar way of nerfing Baton Pass it'd be great - the issue with restricting X amount of teammembers to holding BP is that, as you said, even 4 BPers can crush stall teams on their own - and you can go without Mime and Smeargle/Zapdos to keep Scolipede, Espeon, Sylveon and Vaporeon (arguably the vital members). but then this leads to a snowballing shitfest of an argument where people argue about the number that X should be. "why not X+1 if I don't use Y Pokemon?" - or "why not X=6 when I don't use Espeon or Scolipede" etc....
To those of you who are saying Baton Pass is uncommon, play some upper Ladder like
Jukain and some other players have mentioned. I actually pinched the Musharna set posted earlier on - the one with Imprison and Baton Pass - and placed it on my own BP team, solely to screw with any other Baton Pass teams i came up against. I counted the amount of matches against BP that I had yesterday, and it was around the 30% mark. I also ran the stupid things that people mentioned, including Prankster Haze Murkrow. I basically siwtched it into Espeon's Stored Power and clicked Haze. It's not viable at all outside of that, and in every single other non-BP match I basically threw it in to die/it got off a Prankster Thunder Wave or two.
hipsterdrowzee
banning Speed Boost is not an option at all - Speed Boost Scolipede, Sharpedo and Yanmega all make for great Pokemon in the lower tiers, and even in OU, as late game cleaners - which is a very legit strategy. Blaziken was broken because of Baton Pass, yes, but the other Speed Boosters aren't broken at all on their own.