So heres the thing about everyone's favorite pincushion. While it itself is a very weak mon , the MOST viable other terrain setter is... Indeedee. Rillaboom will join the fray soon, but until then Pincurchin makes for an ok hazard setter, can pivot with volt switch, and has access too sucker punch for some reason. With only one other terrain setter with an ability in the game currently, Pincurchin is arguably the better of the two in singles due to its abysmal speed.
An interesting argument can be made about Iron leaves though. It is the first pokemon too benefit from three terrains for the purpose of STAB/abilities. Grassy and Psychic boosts its base stab and electric activates both Quark Drive and Psyblade. Given it's good speed and spdef, you could even argue that Leaves could be a good hard Terrain setter with the electric seed. +1 def and either a speed or attack boost from quark drive could be decent with proper team building. The one mon truly holding Leaves back though is Gholdengo.
I think an argument can be made for a multi terrain based team with powerful partners. A core I have been theory crafting is Hawlucha/Pincurhin/Iron Leaves, with either Arboliva or Indeedee in the reserves. The 3 I mentioned cover each other very well defensively and tick off all the needed boxes. Priority, speed boosting, possible hazards, pivots, etc. I haven't fleshed out an ideal set/ ev spread yet, but I think the core could be sound at least until the release of Rillaboom.
My issue with using the other terrain setters for Iron Leaves is mainly that the crazy Psyblade calcs come from the Quark Drive boost AND the 50% BP boost hitting at the same time. For example, if we do that same damage calc against Gholdengo under Psychic Terrain:
252 Atk Choice Band Iron Leaves Psyblade vs. 4 HP / 0 Def Gholdengo in Psychic Terrain: 69-82 (42.3 - 50.3%) -- 1.2% chance to 2HKO
It's basically doing about half as much as under Electric Terrain, which at that point I don't think is really worth it if you're planning to break through stuff with Psyblade. I feel like if you aren't going to have Electric Terrain set up, you might as well try the whole late game SD sweeper idea, or run Night Slash to at least hit Gholdengo hard. And to be clear, while I'm interested in Iron Leaves partly because of its interesting bulk as an SD mon, and partly because "wow this does insane damage under Electric Terrain", I'm not sure if it'll really be a major mon, certainly not important enough to run Megahorn for mirror matches at least!
I haven't done the calcs yet for self activating Electric Terrain with a seed yet though. I actually sorta want to do that with some other paradoxes later and see if anything interesting comes about!
The ruins will be legal next season, and just a random Chi-Yu thought
Anyways, now that we know that the ruins will be legal starting in April with Regulation C, I figure now is a good time to bring them up! I haven't done any super interesting calcs with them yet, though I think from the November metagame, we all know that Chi-Yu, Chien-Pao, and Ting-Lu are likely to be MAJOR metagame forces, and maybe Wo-Chien will carve out a niche between Meowscarada and Brute Bonnet...
Anyways, an interaction to remember about the ruin abilities is that the same abilities are immune to each other. So for example, Chi-Yu is immune to the Beads of Ruin from another Chi-Yu. This has led to this fun little meme calc we've talked about on Discord before, I think around the time OU banned Chi-Yu!
252 SpA Choice Specs Chi-Yu Overheat vs. 0 HP / 0 SpD Assault Vest Chi-Yu: 49-58 (37.6 - 44.6%) -- guaranteed 3HKO
So that's still a hefty amount of damage, but yes, AV Chi-Yu can avoid getting 2HKOed by Chi-Yu's STABs! Of course, things change if it Terastallizes:
252 SpA Choice Specs Tera-Fighting Chi-Yu Tera Blast vs. 0 HP / 0 SpD Assault Vest Chi-Yu: 120-144 (92.3 - 110.7%) -- 56.3% chance to OHKO
So yeah, AV Chi-Yu is not some hilarious wondrous counter to Specs Chi-Yu, and Chien-Pao has even more to worry about considering its access to Sacred Sword for mirrors. And admittedly, I feel like people might just stick to making the big AV mons fire-resistant (Tera Fire Bax already makes sense for some match ups tbh), but this meta hasn't started yet so I could be totally wrong about these predicted developments! And of course, I expect Chi-Yu is still gonna be pretty vulnerable to Focus Sash cheese and the crazy amount of priority likely flying around when it enters.
Still, I bring it up for a reason beyond the memeing: I do wonder if there might be some more clever ways around Chi-Yu (and to a lesser extent, Chien-Pao). I think these two are going to be huge offensive forces, and defensive counter-play is likely to be tricky, though maybe not as hard as OU due to the "trading blows" nature of 3v3 maybe being more accepting of high power, as we've seen with Flutter Mane! At the very least, maybe AV Chi-Yu might make sense as a back-up item when you need say, choiced items on other stuff, 55 / 120 SpD isn't the worst thing in the world I guess!