I'm certainly not a metagame expert but as someone who was there for and voted in the original XY Baton Pass suspect test, used a lot of different BP team structures pretty extensively on the BW and XY ladders (I won't claim to be a tournament-level player though), and has seen the evolution of the strategy in response to bans firsthand, I do feel at least somewhat qualified to speak on the subject.
Probably the thing that interests me the most about this cat-and-mouse game of restricting Baton Pass and adaptations to the bans taking place is how
conservative the original approaches were. There was this targeted intent not around eradicating these broken elements, but around minimizing as much collateral as possible, to the point where
banning the move wasn't even on the table to vote for the original test. And it was something I personally agreed with. Baton Pass was a diverse strategy with a wide range of applications and it didn't make sense to restrict all of them when the problematic element was seen as the full pass chains specifically that were simply just one application.
Then smaller pass chains were optimized and seen as still broken, and banned. Then quickpass was further optimized into an overbearing strain on the meta, and that was banned as well. I'm pretty sure there were even more increments, steps, and bans taken than this, I don't really perfectly recall every step of this history so correct me if I'm wrong.
The way I've always seen it was that Baton Pass has just been a pie chart of a massive wide range of strategies and uses and applications, and it was originally thought that the broken strategies were just a small slice of that pie that meant that the collateral of getting rid of the move would be unnecessarily large. Then as time passed and the metagame developed with further optimizations, a bigger and bigger chunk of that pie was seen to fall under the "broken" category, and subsequently banned, going gradually up until a huge majority of that Baton Pass pie chart falls under the "broken" category with only a small chunk of it remaining being "balanced" uses. And as as result, a movement to preserve any collateral and non-broken Baton Pass uses by complex banning the specific issues that started out fairly reasonable has gotten less and less justified as time has gone on.
In my subjective opinion, I think that BW in the current moment is teetering right on that line of justified preservation, maybe leaning towards "why not just ban it all at this point". One-mon quickpassing for stats without speed is still allowed and still in theory allows for a good number of different applications (in practice certainly won't align and be prone to meta shifts), removing a good chunk of the move's competitive uses but preserving a lot of remaining strategies. I could absolutely see the arguments and justifications for keeping it if it's not breaking the meta right now. But if the meta develops such that quickpass ends up being seen as too much to handle, it makes me seriously question the actual point to complex banning away this move to a version of itself that can only accomplish just a miniscule fraction of the options it was originally designed to bring. Every notion that a more optimized current quickpass can break the metagame pushes it further and further over that "why even keep it?" line that I personally think it's already been leaning over as-is. I've enjoyed using a NastyPass Celebi team in the modern meta and don't think that it seems to be broken (I certainly have no idea how good it actually is in tournament play) but I don't think that it's a strategy that desperately needs to preserved in the tier as a top priority.
I can't really agree with prioritizing things like keeping Celebi's viability in the tier at all costs? I can understand the reasoning behind doing so in terms of specific broader meta health like making Keldeo more manageable, but in terms of "it's an unfair victim of collateral damage", we've already locked Venusaur and Dugtrio into tiers that they don't belong into because of how they abused elements that were deemed broken. Drypassing certainly isn't broken, but I find it hard to argue against the notion that Baton Pass as a generalized move and singular cohesive entity
isn't considering all of the bans that have been taking place around it. "Drypass" isn't a standalone move that we can selectively choose to ban or preserve on its own based on its own individual merits of brokenness, it's just a smaller part of the proven broken element "Baton Pass". Should the entire rule system surrounding the tier warp itself around one specific use case of one specific Pokémon's one specific move? If the pie chart says the move has been deemed broken in almost all of its applications, then it's certainly a banworthy move. We've generally avoided banning "parts of things" whenever it isn't absolutely necessary.
I don't want to comment on ADV or GSC because, not only am I not familiar with these metagames or even remotely qualified to talk about them at all, I also believe that actual meta health and impact should be preserved over cleanliness of tiering and bans. BW for example has complex banned away Swift Swim and Chlorophyll, something that I think makes absolutely no sense considering that the abilities are
broken in their unrestricted state but also preserve no meaningful collateral through the complex ban (manual rain and sun setting are completely unviable, Kingdra Sand is a memey matchup fish at best and basically not a thing at worst, certainly not a notable element of the metagame that needs to be preserved, and the "but Cherubi" argument is nonsensical when we already banned Sandshrew), so it's a case where I think the complex bans are unjustified and only serve to muddy up the tier with no benefit. I'm personally similarly skeptical of the notion that BW needs to preserve a complex Baton Pass for the sake of meta health when it seems like little of value would be lost by just getting rid of the thing that already proved broken in almost all of its applications ESPECIALLY if the current rule is deemed "not enough we gotta restrict it more", but if ADV and GSC players believe that it's an element that should stay for the better of the metagame then I don't see any reason to force the ban onto them. I think that there's benefit to simplifying an overly complex ban that's already basically getting rid of the move as-is, but there's certainly no actual benefit to standardizing a rule across all tiers that are fundamentally not the same and don't warrant the same tiering action in context.
But overall I agree heavily with
Plague von Karma's sentiments, at least with regards to BW. Historically, there's been a tiering goal of minimizing collateral damage that I think made justified sense back then and has had less and less ground to stand on as time has gone on, up until now where it's still lingering on through complex bans that basically just feel like the ghost of past incremental steps when the modern state of Baton Pass in the meta and its much wider spread of apparent broken uses would certainly have warranted a full outright ban.
EDIT: Spoke to some others on Discord about the current state of the meta and edited a few things. For the record I'm fine with preserving drypass in BW if the meta impact is deemed positive enough to be worth the complex ban tradeoff. I'm not an expert, I've just been trying read the room based on ABR and Finch's assessments. I'm very much anti-complex ban, but I don't think it's the end-all be-all and can see the arguments to keeping one. How far backwards we should bend over for this kind of thing is certainly a complicated and not a straightforward issue.
Not that I think that preserving Celebi's viability through an unnecessary complex ban for the sake of meta health should be the path taken over just putting a Keldeo ban on the table but that's a far stray off-topic.