I'm going to preface this by saying this is going to be unpopular (haha me if you must) given the imminent approach of DPL, but given the lack of a release date for Pokemon Home and the very realistic possibility that we will be playing pre-home for as much as a couple more months, I feel the need to make this post, as I haven't seen much discussion regarding this. I have played extensively over the last month, even maintaining rank 1 on the ladder for about a week, and I feel that tiering action is needed to have a competitive metagame until home releases. The offensive treasures of ruin are, to be perfectly honest, too much for a pre-home metagame to handle, particularly in combination with offensive partners such as Iron Bundle and Dragonite, and I believe both Chien-Pao and Chi-Yu need to at least be suspected. I was content to play the meta out, but I fear that Home may have been delayed and I really don't think this format is suitable as it is for two months of DPL. It's hard for me to imagine myself enjoying playing SV in its current state for potentially 11 weeks without getting burnt out.
TLDR: Both Chien-Pao and Chi-Yu deal absurd damage and enable otherwise benevolent partners to sweep games, yielding a very risky and unhealthy metagame. Generally, not being able to switch out of a stat reduction is a massive L that prevents typical defensive counterplay.
I'll start with Chien-Pao. Ever since the beginning of SV, the combination of Dragonite and Chien-Pao has been popular, but it has felt particularly overbearing in the aftermath of the banning of the two best ghost types in the tier. On paper, the issue may appear to be Dragonite, the same ridiculous damage output exists with Palafin as well, although less used due to the opportunity cost of not using Dragonite. Although priority blockers exist, and are pretty much mandatory in this format, the issue is that Chien-Pao has the tools to beat all of them. Farigarif can be easily felled by Throat Chop, Tsareena is countered by Ice Spinner, and Indeedee's utility is weakened by both. I don't even need to mention Bruxish, whose lack of bulk makes it unviable for the role. Although surprise Tera-Ghost is a decent way to check espeed, I would argue that necessitating a tera use in order to check a common team archetype wholly proves the brokenness of this combo. If one loses their checks to espeed, the combo will easily sweep through the rest of most teams. Even Rotom-Wash,
a traditionally bulky Pokemon, needs 252 HP evs and 72 defense evs to guarantee survival against tera normal espeed with Chien-Pao support. Note that this calculation becomes much more reasonable without Chien-Pao.
One counterargument to all of this would be that dragonite often consumes a tera in order to access immediate KO potential, but it doesn't need to tera to rack up extensive damage. Dragonite tera mindgames can be particularly brutal, as normal's only weakness being fighting makes it very risky to call a tera with, say, a
Great Tusk (turn 6).
This may all sound like a case to ban Dragonite, not Chien-Pao. However, Chien-Pao enables this ridiculous damage output with sword of ruin. Without Chien-Pao to accompany it, I think Dragonite would be fine. In addition, there are alternatives to Dragonite that could be used if it got banned. As an example, Lucario also gets Inner Focus as well as extreme speed, albeit with less attack, but access to swords dance. I fully believe Chien-Pao to be the problem here. Personally, I feel compelled to include Farigarif or Tsareena on most of my teams
that do not themselves have a Chien-Pao. Chien-Pao has a very centralizing impact on not only the teambuilder, but also in battle, often preventing safe play due to its coverage complimenting Dragonite so perfectly. While yes, you can counter this strategy, I think there should be counterplay beyond correctly calling which mon Chien-Pao is targeting and whether the Dragonite will call the Farigarif switchin (as I had to do in
this replay). Yes, this strategy is beatable, but I think the playstyle it enables is unhealthy.
This Pokemon was an absolute menace in early SV when paired with Flutter Mane, with some calling for it to be banned, but it fell off the radar following the Flutter Mane quickban (too quickly I would argue). This Pokemon functions differently than Chien-Pao in its own capability to sweep games by itself without relying on a partner, with 135 Special Attack and opponents' defenses stuck at .75x (singles players noted a short time ago that Chi-Yu has effectively base 192 special attack, which I think puts in perspective how strong this Pokemon is). Its mere existence makes trick room a
risky bring, and literally nothing in the format bar its own AV set can sustain a double up of a Chi-Yu and an Iron Bundle. I think this Pokemon is much more straightforward in its brokenness than Chien-Pao, it's just really difficult to live a hit and it is so strong that
even truly outlandish sets can win you games. Its biggest weakness is its average speed, but it pairs quite well with tailwind (see Stax sample) and it is fast enough to outspeed most Pokemon in a pre-Home metagame. It is also checked by Chien-Pao teams, but it is always noted in tiering policy that "broken checking broken" is not an excuse to allow something in a tier, and without espeed spam Chi-Yu would be truly monstrous.
With all that being said, I would support a suspect of both of these mons, although I highly doubt this will happen given the timeline. I just want to put my word out for a closer look at the metagame with Pokemon Day not clearing up questions about Home release. This post may be proven irrelevant soon, I hope (please ILCA, please). For what it's worth, I think both mons will be even more banworthy post-home, as stronger offensive options will pair strongly with them and further limit counterplay.