After I found out that council voted 5-4 to quickban Drifloon, I thought I would voice my opinion here. Now, I’m against banning Drifloon overall, but I’m just going to argue that at the very least this should be a suspect test rather than a quickban by the council.
Firstly, let’s talk about the quickbans that occurred in previous weeks. Gastly boasted an amazing speed, deadly special attack, and an incredibly broad movepool. It was able to OHKO and 2HKO basically the entire tier with the appropriate coverage move, and it even had priority in the form of sucker punch if a weakened scarf mon tried to revenge kill it. The only defensive answer, Munchlax, lacked the ability to OHKO gast (unless it was running ZHB which had a whole other multitude of issues) and resultingly would be forced into passively spamming recycle. This made it very prone to getting sludge bomb poisoned, which really hurts its survivability. Overall, Gastly fit the archetypical mold of a broken offensive mon.
Gothita, on the other hand, provided insurmountable support for all team styles. While its most common set was choice scarf due to the offensive nature of the Gastly meta, it could also run a more bulky eviolite + 3 attacks set, and even calm mind or PP stall. Due to the sheer amount of different sets that Goth was able to run, there was always essentially one variant of goth that your team would be weak to. There wasn’t any real opportunity cost to trapping a mon either, since PP stall variants could just switch out before you struggle to death, and all the dark-type set up sweepers (Pawn&Scraggy) are relatively easy to deal with for most teams.
And lastly, there’s Cherubi. Though there was some controversy surrounding whether or not to ban Vulpix as opposed to this mon, the combination of the two was undeniably broken. Grass and fire coverage is nearly unresisted in the entire tier due to the lack of decent fire types overall, and its 150 base power Weather Ball is hitting pretty hard anyways. If Cherubi ever had a free turn to set up growth (which wasn’t always that difficult given the extra bulk eviolite provides), your only counterplay was attempting to stall out sun by switching between your grass and fire resists, hoping you guess right each turn. Trapinch couldn’t even revenge kill Cherubi with First Impression because it has the free moveslots to just run protect.
Now, what is it that makes Drifloon so threatening to begin with? It has good STABs, decent bulk, variability set-wise, and blazing speed in tandem with unburden. It primarily has three sets: physical, mixed, and special. Physical runs acrobatics, thief, will-o-wisp, and sub; mixed runs acrobatics, hex, will-o-wisp, and sub; special runs hex, calm mind, substitute, and thunderbolt/will-o-wisp. On teams weak to hazards it can also make room for defog, and on sun teams it can even sometimes use weather ball. It can also even use destiny bond or memento to some extent. While the physical and mixed set work well on their own, the special set paired with Mareanie for toxic spikes support is typically viewed to be its strongest set.
However, despite Drifloon being very threatening and unpredictable, it is notably different from the three aforementioned mons; Gothita was a different issue altogether so I'll try and draw comparisons to Cherubi and Gastly. Unlike those two, Drifloon can only really threaten to sweep once per match. It can’t really just come in, wall break for a bit, and then threaten to sweep later. This not only limits the opportunities to come in, but also means that Drifloon's sweeping opportunity is shut down by a single mistake. Gastly had a much more effective speed tier, priority, and the potential to run a Choice Scarf. Cherubi needed external support from Vulpix to double its Speed, which made it less splashable but didn't lower the brokenness of the Vulpix-Cherubi core, which came from the fact that it could double its Speed easily and repeatedly. Drifloon is a lot more threatening than most of what we have available, but that makes sense - it comes at the significant cost of only being able to sweep once.
Furthermore, Drifloon lacks immediate power, as it needs to either set up for a bit with CM, or pop its BJ to deal relevant damage. This means that each set has its own hard walls. Physical Drifloon is dealt with really well by eviolite Onix, eviolite Chinchou, eviolite Pawniard, eviolite Ferroseed, and pickup Munchlax. Mixed is dealt with easily by Munchlax, Vullaby, and Pawniard. Special is also dealt with by Munchlax and Pawniard, and it also needs burns/poisons/other status or a couple calm minds to actually be threatening to other mons. Though unconventional, Oddish teams do well vs this set too. CM Drifloon teams typically rely on Diglett to remove the toxic spikes that Mareanie sets, so they tend to get completely crushed by Oddish sun. It's worth noting that while Drifloon can invest in bulk or offense, it can't do both, so a variety of healthy mons can still deal with a weakened Drifloon on the revenge-kill even if it has managed to preserve Toxic Spikes and remove every single one of your checks. What this means is that unlike Gastly or Cherubi, Drifloon has clear counterplay. Compare Drifloon's counterplay options to Cherubi's or Gastly's, which are far lower in quantity or at least viability.
If you still need a 100% counter to all Drifloon sets, pickup Munchlax is a good choice. This set has viability outside of just countering Drifloon (which cannot be said of Cherubi hard counters like Litwick/Growlithe), as it can be used to beat Vullaby in a 1v1 scenario. Burn isn’t even that big of a deal for Munchlax, because, while Double-Edge is generally superior, Façade also works as an okay normal STAB. Pawniard also checks all Drifloon variants, but it doesn’t appreciate being burned and is more prone to getting trapped than Munch.
Part of Drifloon's strength is versatility, which makes sense because its individual sets wouldn't be nearly as threatening if we knew them from team preview. Because Drifloon has the ability to work around to some extent its checks and counters depending on the set, when playing around an opposing Drifloon it’s important to scout. Unless there is a Mareanie and Diglett on the opposing team (in which case it’s almost guaranteed to be CM with Thunderbolt) , you can’t really know for sure their set until the game starts. In which case, as long as you don’t put your BJ mons in a position to have their juice stolen by Thief until the opposing Drifloon reveals their attacking moves, you’re not really in too bad of a position. The mons that check Drifloon’s various sets are good mons in and of themselves, so more likely than not you’re going to have multiple that check it on a single team already, making scouting for Thief simple enough.
Despite all this, some people may still find Drifloon too much for the current meta. But at the very least, I hope that we can agree that Drifloon, while powerful, is on a completely different level from the other threats we have already banned. At the bare minimum, a suspect should be done on Drifloon to determine whether or not it should stay in the tier as opposed to being grouped in with mons much more clearly broken than it and getting quickbanned.