Wait is the argument here that baton pass is broken?
The reason the metagame struggles to beat Baton Pass is because it isn't commonly seen. There are lots of viable sets that can be used to combat BP is it became popular enough -- just because it is struggling now doesn't mean Baton Pass is broken. It's simply not used enough for the metagame to bother adjusting.
I suppose that we should all teambuild and prepare for threats like Seimsitoad, because while no one ever uses it, it could certainly be a threat!!
(In this instance, I think usage is a strong argument. When the usage stats are as low as this, when Smogon is advertising Baton Pass and players still aren't using it, I think that says something.)
This post leads me to believe that you didn't even bother to look at a single page in this thread.
In the current BP-focused ladder, using Baton Pass is only somewhat reliable but STILL entirely matchup based. I am currently laddering at around 1800 (where you no longer see shit like musharna and malamar), and I can consistently win roughly 75% of my matches based on match-up alone using Baton Pass. This also takes into account Thundurus-I being on nearly every team I'm up against.
I would argue that Baton Pass is broken, and that it is used fairly often at the top of the ladder (especially 1850+) but this is debatable. However, while there are legitimate counterarguments to Baton Pass being broken, I fail to see how the strategy isn't completely toxic to the metagame's development. The impact it has on the metagame as a whole is obviously bad, but some types of teams are affected much worse than others.
Impact on offense: As BP usage/awareness increases, fully offensive team usage increases as a result. Also, Thundurus-I/Mega Pinsir usage increases. Thundurus-I in particular has very few defensive counters outside of Spdef Hippowdon and Bulky Zard X, especially considering that Knock Off severely punishes almost anything else. Offensive teams generally have the best match-up against Baton Pass, but only if Baton Pass is specifically accounted for. The biggest difference between offensive vs stall checks to Baton Pass is that most offensive checks are viable outside of dealing with BP. While the impact of BP on full offense is the least detrimental, it still limits offensive team building and rarely has an unfavorable matchup against any offensive teams, unless the team has Thundurus AND Pinsir/Talonflame or the specific anti-BP Thundurus set with both Nasty Plot and Taunt.
Impact on stall and semistall: Stall really gets the shitty end of the stick when it comes to Baton Pass. The cookie-cutter stall cores consisting of Skarmory, Chansey, Venusaur, Heatran and Aegislash have little hope of breaking any BP chains. That is, unless the stall team carries one of the very few unreliable and unorthodox answers to Baton Pass: Taunt Sableye and Haze Unaware Quagsire. Barring anything even more obscure, these two pokemon are the ONLY defensive answers to Baton Pass that are still viable in the metagame, which means that top-performing stall teams NEED to have them (see: overcentralizing) and
still struggle.
Impact on balanced: Balanced teams lack the ability to exert as much pressure as offensive teams can exert against Baton Pass, and thus balanced teams need to rely on specific pokemon to get the job done. A vast majority of the setup-sweepers in the tier can be handled by Vaporeon and/or Smeargle (roar and spore respectively), which means that balanced teams usually need at least one member that is tailored to beating Baton Pass. The matchup between balanced and BP is heavily in BP's favor, because balanced teams are completely reliant on members such as the aforementioned Thundurus-I, Pinsir, Quagsire and Sableye, as well as a few other viable answers including Talonflame and Taunt Mega Gyarados. Unlike offensive teams, balanced teams have little chance of falling back on offensive pressure if their BP check can't get the job done itself.
Impact on bulky offense: This suffers from the same problems as balanced. High speed, power and offensive pressure are exchanged for defensive typings and bulk, both of which are completely useless against BP.
tldr Baton Pass severely limits metagame development and variety in teambuilding. It has no business being part of OU.