Nerfing Baton Pass is absolutely silly. This is an example of people's wanting to ban things they simply don't like instead of banning/nerfing it due to a lack of reliable options to deal with it that have utility outside of countering Baton Pass, which isn't the case here. People are having trouble with Baton Pass--or, rather, dislike it--due to a fundamental lacuna of the play-style.
Baton Pass' goal is simple: These teams are meant to be a collective aggregate that is an impenetrable piece armor that can also sweep with impunity. However, the problem with Baton Pass is inherent to its design--every Pokémon matters. If even one Pokémon goes down, the entire team is in serious trouble, and the Baton Pass player is in great danger of losing without some serious creativity.
The keystone to every good Baton Pass team is not Espeon but Scolipede. Granted, Espeon's Magic Bounce ability is essential, for it prevents Roar, Whirlwind, and status; however, Espeon is so frail that it is completely reliant on passed defensive boosts, or Substitutes, from Scolipede, and others, in order to be remotely effective. Scolipede proves so dangerous because, as we all know, it can gain Defensive and Speed boosts easily and simultaneously, both of which are critical to creating that impenetrable piece of armor. As a result of this fact, Scolipede, also, usually is the lead.
So, considering that it usually only takes one KO to significantly weaken a Baton Pass team and that Scolipede is usually the lead, the answer to countering full Baton Pass teams is simple: KO Scolipede before he accumulates an absurd amount of boosts to pass and proceed to win the game. But exactly how do we do that? From the top of my head, one Pokémon is the answer: Talonflame.
Both the Choice Band and Swords Dance variants of Talonflame, a very common OU Pokémon, put Scolipede--and Baton Pass teams by extension--in a very awkward position. Any intelligent player with Talonflame facing a Baton Pass team with Scolipede, which they almost always are, should always send out Talonflame first; there is no reason not to. Swords Dance Talonflame can proceed to set up, whereas Choice Band Talonflame can start Brave Birding.
Scolipede can only respond to this threat in so many ways, none of which are very effective. He could use Iron Defense first; however, Talonflame could either use Swords Dance or Brave Bird first, which will put his HP in a dangerously low place. He could use Protect, which buys him a turn, at least; however, that gives Talonflame a free turn to set a Swords Dance. He could switch; however, most Baton Pass Pokémon are defensively frail. Talonflame could rip through most of them, especially Espeon, easily.
Also, what's great about Talonflame is that he has utility outside of countering Baton Pass. He's not some random niche Pokémon.
Though this is only one example of Baton Pass' flaws, this strategy (which is not mindless, might I add, for any good player needs an answer to threats like these, for which there are not many) is not invincible. It's actually far from it. In my own personal opinion (Disclaimer: I only speak for myself here), the community has become stuck to their usual sets and ways, and many are no longer evolving with the metagame and looking for out-of-the-box solutions to new threats. Although Talonflame is by no means unusual, sending him out first is an out-of-the-box strategy, for he normally would not be set out like that; however, sometimes taking these risks are entirely appropriate, especially when they net a win. Are not good players supposed to make these risks? They are necessary in Pokémon.