I just happened to stumble upon your guys’ discussion about OHKO moves and I wanted to drop my horrible opinions on them that no one asked for. I’m just going to go ahead and say it- if there’s one generation of OU where I feel like OHKO moves could be at least palatable from a competitive standpoint, Gen 1 is that generation, at least for me.
The difference between Gen 1 and other generations in regards to OHKO moves is twofold. First, the accuracy of OHKO moves has something to do with Speed in Gen 1 only, though I can’t remember how exactly the mechanics work off the top of my head. The other difference is just how bulky Gen 1 is compared to other generations, in the sense that there’s not a whole lot of other viable options to make offensive progress in the same way you might use moves like Thief or Knock Off for item removal or entry hazards to punish your opponent’s switching.
Gen 1’s bulky environment actually lends itself pretty well to competitive implementation of OHKO moves in my opinion, since that extra bulk generally equates to more opportunities for Pokémon to actually click their attacks before being forced out. In this sense, OHKO moves serve as the great equalizer some underexplored Pokémon might need to function at all, both by being enabled by Gen 1’s bulky environment and by allowing these Pokémon to make offensive progress within said environment. Allow me to cite one of Gen 1’s most recognizable Ground-Types as an example of why OHKO moves could be healthy in reasonable cases:
Dugtrio’s Gen 1 iteration is perhaps best known for being a staple in UU, but one of the reasons it doesn’t see more use in OU is because this tier is far faster, stronger, and most of all, more equipped to take Dugtrio’s hits. With its access to a 30% accurate Fissure, though, Dugtrio gains the option to fish for the chance to brute force its way through most any defensive check that’s not a Flying-Type. I can definitely see why this can be interpreted as uncompetitive, but from my perspective this isn’t too different from other offensive Pokémon in later generations fishing for, say, a 30% Scald burn or a 30% Thunder paralysis. The thing about these offensive OHKO users are that they generally don’t contribute much of anything to the rest of their teams defensively, creating significant opportunity cost even if Dugtrio were to land a game-changing Fissure against, say, a Reflect Snorlax or Chansey. In any other OU metagame, Dugtrio (especially with Arena Trap) may be able to try and fish for multiple Fissure rolls within the same battle if it were to come in on Pokémon that can’t threaten it, such as a Choice-locked Electric-Type move or bulkier grounded targets should the Dugtrio opt to run a move like Substitute on a predicted switch. In Gen 1, though, there’s not much stopping Dugtrio’s Fissure or a Normal-Type OHKO move from being dead weight against a well-played team with a Zapdos or Gengar respectively. In fact, in the case of Zapdos, a full-health Zapdos can even come in and avoid the 2HKO from Rock Slide without a critical hit and set up Agility in Dugtrio’s face, prompting a lose-lose decision on the Dugtrio player’s part. If Dugtrio’s trainer to regain switch advantage by bringing on their teammate Rhydon, they’ve more than likely made the decision to severely limit Dugtrio’s ability to come back in lategame unless one of its teammates faints. If the stars align, though, and more importantly, if the Dugtrio trainer plays well, I can absolutely see a situation where an OHKO move opens up opportunities for the rest of Dugtrio’s team in a midgame setting without necessarily making the battle a free win.
Other possible OHKO prospects in Gen 1 all carry significant opportunity cost as is that keeps them from being considered for every team. Therein lies the beauty of the situation, though: if these OHKO move users already have viable counterplay anyways, and if the ratio of reward to opportunity cost is generally in favor of the Pokémon that would be most likely to be targeted by OHKO moves, I don’t see a problem with keeping these moves legal because of the unique positive metagame interactions they can create in Gen 1 specifically. Dare I say, OHKO moves in Gen 1 feel like they do take some semblance of skill to use effectively, given the fact that they carry more opportunity cost negatives than just their shaky accuracy. This isn’t something like the existing accuracy-lowering moves debate happening in Gen 3 right now, by comparison.