(Im in phone so sorry if bad grammar)
It depends on stuff like the move, and the level of distribution
Defog on Flying types/Pokemon with Wings/Bird like pokemon? Lets fucking gooooo
Knock off? As long as it remains on dark types or fighting types with hands sure
Toxic? On poison types and Specific mons like Quagsire? Sure
All of these 3 on a massive scale distribution? Fuck no, we just need some more variety, not another pasive agresive toxic/knock off spam like gen 8 my beloved
Edit: as you can imagine, I hate how gf doesnt have common sense in distribution, why the fuck does meow learn spikes
Wholly agree with this. Its pretty cancerous that everything learned Knock and Toxic. If everyone has the same moves, it makes already good Mons even better.
I really liked Knock Off distribution in Gen 3. What Mons had the move back then? Alakazam, Hariyama, Armaldo, Banette, Kabutops, Crawdaunt, Sableye, Farfetch'd, Kingler, Lickitung. That is, 10 fully evolved Mons, none of them OU. It was a niche powerful (yes, even with 20 BP removing item was huge in Sand infested Metagame) move that required using an otherwise suboptimal Mon and build a team around that.
Completely different from SS OU, where you have the Move on any Mon. Clefable, Toxapex, Lando-T and Kartana all would have been OU even without Knock Off (unlike Weavile, who absolutely needed it to be viable and almost dominating), but with it, they are even better.
Like already said, I really like what they did this Gen, Knock Off is again limited to few Mons. Tusk would still be OU without Knock Off, but would have been way worse and isn,t opressing even with it. Iron Valiant still would be OU as well, but with one less option. Meowscarada probably would fall to UU, Zoroark Hisui is the one OU Mon that doesn,t need the move and Iron Treads at some point will probably fall to UU even with having Knock Off. Looks a pretty alright distribution, only Mon that I would add to the list is Weavile since I like that Mon a lot, but it not having Knock its a worthy sacrifice for Pex and Lando not having it.
Same for Toxic, if Zapdos and Rotom wall Tornadus-T, I want them to do it consistently, not collapsing to random Toxic turn 1. Its good for the meta to be able to see those moves ahead (due to limited distribution) instead of guessing which of the 6 Top Tier threats will throw it to what you prepared to check them.
Also, to those saying that we need more Defoggers to avoid the HO dominance, that isn,t fully true. There are 2 other options (that of course probably won,t be followed).
1. Ban Rocks + Spikes combination on the same team (similar to BW Drizzle + Swift Swim complex Ban).
2. Ban Gholdengo.
Without either of those, Hazard centric HOs, while still very viable, won,t be nearly as dominating as they are now.