Originally Posted by Fat Poppy
Pokemon has elements of chance, that's how the game is. You can sway the odds in your favour, however, 30% sounds infeasible, but consider, as many have said before, that it's a 51% chance to KO at least one Pokemon over the use of two turns. Why would you attempt to use Sheer Cold on something like a DD Rayquaza? There's a niche use for Sheer Cold on Kyogre, and that Pokemon getting in for free? They risked a 30% chance of dying, 51% if they're slower. Just because it could go either way doesn't mean it's the definition of 'non-competitive', many a time has a game come down to a Focus Blast miss, a Scald burn, etc. Using Sheer Cold against offensive teams is a high risk, high reward strategy, but the risk is much higher, meaning you'll lose most of your games. Losing to a bunch of sequential Sheer Colds hitting may seem 'unfair' or whatever but there is nothing to differentiate that from 'competitively' losing to an Arceus crit or any other random roll of chance.
Also, more often than not there is a workaround to most things - Mamoswine can check as many Rayquaza as it wants, Yache Berry Rayquaza lacks the power to get through Ice Beam Arceus; almost no strategies are foolproof (and if there are some I'd like to know) and the metagame can usually adapt.
Are you telling me that Ubers, the land of the game-ending setup sweepers, is going to simply accept a near-70% chance to let a Pokemon switch in and use whatever move it pleases? With some Pokemon, it's even a 49% chance to use two moves in a row absolutely for free. What if, for example, your opponent switches in DDquaza, uses DD, lives through both Sheer Cold attempts, and then sweeps you? Let's say one of your Sheer Colds works. What if they then switch in ANOTHER setup sweeper and do the same thing? It starts turning into a game of "are you feelin' lucky, punk". A successful setup can quite often, depending on the team in question, result in an immediate sweep with little to no recourse. And supposing you prepare for setup sweepers appropriately, what do you do about the powerful mixed/choice sets? They switch in on Sheer Cold, have a 70% chance to live, and then fire off whatever move they like-- and if your team is based around revenge killers for setup sweepers, chances are you're not going to have much to tank those choice moves.
It's either going to suck, or turn into a crapshoot. It's not like other moves because it's all or nothing with a low chance of happening. If you Scald something praying for a lucky burn, you get a little out of it even if it doesn't burn. If you Toxic something, you can expect it to poison a reasonable amount of the time, and it's generally a target for bulky Pokemon in any case so it's not a huge deal to miss once or twice. But OHKO moves turn the game into a nasty deal where one game a Pokemon can hard counter you, and the next you kill it instantly. And there's no skill involved with playing around their Pokemon, unless you consider prayer a skill. You yourself have demonstrated that it's very close to a 50-50 chance regarding who wins with every encounter between Sheer Cold Kyogre and any counter not named Shedinja. No skill there. It's not like where you use Fire Blast and have a 15% chance of having to rethink your game plan. A dead 50-50 chance means that who wins and who loses is entirely based on a coin flip, and this will happen every time you use Sheer Cold Kyogre (as opposed to more fringe cases like speed ties). If coin flips to determine a significant portion of battles isn't non-competitive, then I desperately need someone to tell me what is.