Oh i’m sorry, i specifically meant how would we hypothetically play OU if the water and steel types were banned and restricted to ZU and any lower tiers, not just the pokemon, the entire type, full stop with no comma
The only Ice resists left would be Fire and Ice types. Ice type attackers + rocks would break the entire tier. So would Cornerstone, I'd imagine. A scenario where Kyurem stays seems increasingly difficult to justify due to an increased lack of resistances.
Stall would also lose Dozo, which is crazy. I'm not a stall expert, so I won't make a claim that stall would be dead. Many stall players are quite resourceful. It would be a huge loss nonetheless. Same for Alomomola on a lot of bulky balance structures.
Toxic would be stronger without one of the main immunities to it. T-spikes would still be limited by Poison types such as Glowking and Pecharunt. But Dark and/or Ground type attackers might be more threatening on T-spike teams due to the lack of Gambit and the metal birds.
Roaring Moon would become even crazier without steel types to resist Acrobatics or Dragon STAB, but people would likely pretend not to notice.
Now let's talk about weather. Rain is dead without setters and many of the abusers being yeeted out of the tier. Sun gets a pretty interesting buff. Fire spam in the Sun would be much harder to stop as one of the main resistances in Water types are gone. Heatran is very niche, but that is also gone. This leaves just Dragon and Rock types as resists. Sun can actually sort of make up for the loss of Walking Wake with Grass types, which only really need to worry about Dragon types. We might see an uptick in Flash Fire mons just to fill the void.
Tyranitar would likely see a rise in importance. Not necesarily Sand teams since Excadrill is gone. But Tyranitar itself seems pretty decent in this scenario. The combination of Sun teams getting better and balance needing to deal with special attackers favors it. Also, Water and Steel were two types that were supereffective against Tyranitar. Not needing to worry about 2 of its 7 weaknesses is a pretty big deal. I could see Ttar and Sini being quite the defensive core.
Hamurott is a huge loss for hazard stack. Without it, teams can go back to fast Taunt and Magic Bounce to consistently deny hazards. The only question is if Kleavor gets a boost, which I'll get into in a bit. For Webs, Ribombee is fine. I know some people have stated they prefer Araquanid, which is now gone. Webs itself would still be alive and well. Galvantula is also maybe a potential lead option to consider.
Hazards removal be close the same, though. Ghold and Corv being gone more or less cancels out as far as removal. Bulky spinblockers like Sinsistcha and maybe Air balloon Pecharunt would take Ghold's place.
The main difference is Rocks would increase in importance. Steel types are one of only 3 resistances to SR. Their presence is often necessary in teams that aren't boots reliant. Also, the sudden lack of Ice resists which aren't Rock weak would make them rise enormously in importance. Most rocks setters are fine. But Kleavor being OU level would give a similar problem that Hamurott does now. It doesn't help that Kleavor just lost 2 of its 3 weaknesses besides maybe coverage moves. This could actually make it a huge issue.
I suppose we should also talk about increased centralization of Great Tusk. While spinning would still probably be the main way of removal, Iron Treads being gone stings a bit. Possible alternative like Excadrill and Quaquaval are also gone. You likely need to go to mons that are currently RU or below just to find a reliable spinning alternatives. Same for Defog, though, so the reliance on spinning for most teams likely stays the same. The one possible exception might be Geezing, which can now run other abilities besides NG to reliably Defog now. The combination of Levitate and no Steels could actually make it quite good. Psychic could be its only weakness.
One of the biggest changes is the lack of Gambit. While there are other SP mons, nothing really takes its place as an end game win condition. Certain mons that Gambit makes hard to use would become more viable. I'd imagine Horoark is one such mon.
We should also talk about Gliscor. As a hazard resistant and Toxic immune glue mon, it would rise even more in importance. Corv is one of the biggest counters, and so Gliscor would face less resistance without the metal birds around. But Gambit also matters since one of the best resistances to Facade/Knock Off would no longer be in the tier. Steel types in general are a Facade resist, so only worrying about Rock and Ghost types to stop Facade is pretty huge for Gliscor. Tyranitar's increased prevalence maybe helps, but it also isn't Toxic immune.
Finally, Psychic Terrain might just become viable again without one of the main Psychic resistances in the metagame. It's far easier to prepare offensively for opposing Dark and Psychic types with Steel types out of the way. Without Crown, only 3 Psychic type are currently even OU. Hatt, Glowking, and D-speed are likely not enough to stop psyspam. D-speed might even help it. Dark types are an issue, but Gambit and Hamurott are now gone. While there are a number of Dark types that could hypothetically rise up from lower tiers, the biggest problem is Roaring Moon. Moon gets so many opportunities for free turns against psyspam. And since Psychic Terrain stops priority, most things on these teams cannot catch up to a boosted RM.
