IDT grass is bad. Definitely lower tier, but the utility is what makes it stand out (also having a winning mu against water and ground, two great types, is really good).In my post above I mentioned that Grass and Psychic are the only Types that have a losing record both offensively and defensively. Ironically, part of what made Gen 1 Psychic so dominant for so long was that it remains the only Type in any Type chart to have a WINNING record both offensively and defensively, even if just barely. The thing is with both Grass and Psychic, though, is that I would argue they’re at their strongest as utility Types rather than dedicated offensive or defensive use. Tera Grass is one of the best defensive Tera Types in the game in my opinion but that’s only specifically as a Tera Type, and outside of Teal Mask Ogerpon being one of the weaker forms, I can’t remember the last time I’ve seen someone run a Tera Psychic Pokémon on the OU ladder.
Utility, though? Things are noticeably better, and unfortunately held back by the rises of Ghost and to a lesser extent Dark’s offensive spread. Two of the best utility moves in the game, Spore and post-buff Teleport, are these Types. The Terrains may have been nerfed, sure, but gradual healing and especially priority blocking are both excellent tools to have. Moves you mentioned like Psychic Noise and Future Sight thrive off of their respective utility, and Grass and healing and healing have always gone together nicely.
Psychic’s Problems from the perspective of an uneducated guy who has this as one his top three favorite types alongside water and poison:
- Weak to common attacks like U-Turn and Knock Off (and Pursuit prior to Gen 8)
- Poor matchup spreads offensively and defensively
- Several prominent nerfs over various generations
- Not nearly as many new Poison-Types added in newer generations, specifically compared to Gen 1
- Fairy gives Psychic competition for the role of Fighting check
- Generally low base power attacks with more emphasis on utility
- Low amount of parity between top-tier Pokémon of this Type
Resisting bug IDT is too low value, but sure. However, resisting fairy and fighting is big. Fighting is a pretty good type but fairy is prob top three minimum.1) Majority of its resists are low value (Bug, Grass, and Itself are 3/5)
2) It is not only weak to a top tier offensive type, but a common and top tier offensive coverage type, which undermines its defensive profile even more than it looks like
3) Dreadful physical attack options. 80% "accurate" mainstream option, and some don't even get that. Stone Edge has amazing coverage to justify that, Gunk Shot doesn't.
4) Hitting one good type does not mean it has replacement-level offensive coverage. By this logic, Bug (Dark) and Grass (Water; Ground) have good coverage. Five resists/immune (including to three of the best types in the game) and two SE is still a bad profile, even when one of the SE is a good type.
5) Having an immunity against Poison, and it being the best defensive type in a game, makes the type a lot less safe to click on offense in general.
Yes, it's weak to ground, but that's really its only weakness. And secondary typings such as grass and flying are really good pairings with it because of that.
Gunk shot's main thing is that 30% poison rate, which means typings such as ground still don't like switching in. And sludge bomb is just a really good special attacking option.
While poisons offensive coverage isn't amazing, hitting fairy does raise it up a bit.
A big thing I think people are overlooking is the utility of poison. Toxic is a incredibly dominant move and toxic spikes can define entire tiers at times and shut down complete playstyles if they don't have an absorber (which hey, is poison types, so another point for poison)
Poison is the definition of mid tier typing, yes it's not going to wow you with powerful attacks or insane defensive merits like steel, but it does decently in both. Combine that with the utility it provides, and I cannot put it low tier, it's just way better then typings such as ice (which yes, is pretty great offensively, but flounders incredibly hard defensively and even offensively struggles decently hard against top tier types such as steel, fire and water if no freeze dry).