I will bite and post about it further.
You are looking at the Scovillain issue from entirely the wrong perspective. What is important is not the Pokémon's winrate in this situation. The issue is that Scovillain essentially creates non-games due to how extremely polarizing it is. The opponent either has something which is capable of stopping it, or does not. That is what determines the game - and winrate. It makes sense that it would be about 50% as a result. That does make it extremely uncompetitive and very unfun to play both as or against as a result.
Majority of the time, if you have a team that's able to incapacitate a Pokémon, or (god forbid) your opponent makes the mistake of sending out something defensive, not knowing you have Scovillain, and you pivot in to Scovillain, that's the game right there. Nothing they do matters, no skill they have matters, and there is no coming back from simply having a Scovillain switch in.
Here is an example of what I mean -
https://replay.pokemonshowdown.com/gen9randombattle-1795156124
From the moment Scovillain hit the field it was game over regardless of how my opponent played, unless I got extremely with boosts. Nothing else has this type of game-ending potential merely by showing its ugly two faces.
But if he had one of the many answers to it (best example would probably be Skeledirge) Scovillain would be an entirely dead Pokémon, and I'd be in a 5v6 scenario where I'm hard pressed to win.
Take away your argument about 'the winrate is 50% so it's balanced' and ask yourself WHY the winrate is 50% and whether or not what this set adds to Random Battles is positive or negative. Both from a competitive and a fun perspective.
So then my question to you is, if we changed Scovillain's set to a Chlorophyll sun sweeper and then buffed its level drastically (because it would need that), would anything you just said stop applying to Scov?
I mean (and I'm happy it worked out this way lol) I just logged into showdown and randomly generated one team in gen 9 rands with a staff command:
https://pokepast.es/6f7f6d826320ee9b
Sunny Day Scovillain kinda runs over this team. Even being conservative and making its level 86 (it would probably start higher than this):
Lvl 86 84 SpA Scovillain Solar Beam vs. Lvl 83 84 HP / 84 SpD Krookodile: 318-374 (108.5 - 127.6%) -- guaranteed OHKO
Lvl 86 84 SpA Scovillain Solar Beam vs. Lvl 88 84 HP / 84 SpD Samurott: 302-356 (97.4 - 114.8%) -- 81.3% chance to OHKO
Lvl 86 84 SpA Scovillain Flamethrower vs. Lvl 83 84 HP / 84 SpD Cetitan in Sun: 422-498 (100.9 - 119.1%) -- guaranteed OHKO
Lvl 86 84 SpA Scovillain Solar Beam vs. Lvl 86 84 HP / 84 SpD Sandaconda: 306-362 (115.9 - 137.1%) -- guaranteed OHKO
And yes, Scovillain would probably run Sunny Day / Solar Beam / Flamethrower / Overheat because it doesn't learn any other attacks. Its coverage is Crunch or Zen Headbutt. And Tera Blast, but we're not using up a Tera Blast slot on it ever.
I did another genteam for our partners, and we got:
https://pokepast.es/d6659c4bf4298355
These 5 are entirely capable of handling Volcanion and Appletun before ever revealing Scov, I'm sure you'd agree. Medicham 2HKOs both (and, in fact, the entire team at worst) and Volcanion is also the only answer the opponent has to Magearna. Chip it down with Magearna, and Scov can certainly get it into range:
Lvl 86 84 SpA Scovillain Solar Beam vs. Lvl 80 84 HP / 84 SpD Assault Vest Volcanion: 93-109 (35.9 - 42%) -- guaranteed 3HKO
That's
with Assault Vest. Volcanion has so much to do in this matchup that I would basically consider this an autoloss.
And actually, Appletun is a nice Scov check:
+6 Lvl 86 84 SpA Scovillain Flamethrower vs. Lvl 90 84 HP / 84 SpD Thick Fat Appletun: 201-237 (58.4 - 68.8%) -- guaranteed 2HKO after Leftovers recovery
Lvl 90 84 SpA Appletun Dragon Pulse vs. Lvl 86 84 HP / 84 SpD Scovillain: 118-141 (46.8 - 55.9%) -- 23.8% chance to 2HKO after Leftovers recovery
It's a little harder if you have Meteor over Pulse, but Appletun can handle Scov pretty well with either set. And once Appletun comes in, Scov pretty much has to switch out, and if it's Moody then it has to try and set up again with less PP. If it's sun, it just needs to come in and it can still let off an Overheat or something.
The short of it is that Scovillain will always be a matchup fish. I prefer honest mons too -- my favourite set this gen is Future Sight / HVoice / WIshTect Farigiraf -- but GameFreak didn't make an honest mon in Scovillain, and we're only working with what we've got. Lots of, if not most, Pokémon in every gen of rands are matchup fishes. For example, every setup sweeper is a matchup fish to an extent. Some, like Frosmoth, either win the game for you or are basically dead weight, doing a small amount of chip on one mon before turning it into a 5v6. OTOH, Ursaring is a hella mu fish this gen because its last slot is EQ or Crunch, and it is either a menace or hard walled depending on what mons the opposing team has in relation to its fourth moveslot. In Gen IV (my best format) it is not at all uncommon for Regirock or Regice to singlehandedly win the game for one team because the opponent gets 0-1 special or physical attackers respectively. And Regice actually finished last month of gen 4 in 6th place in terms of winrates, which is why winrates are a valid metric. A matchup fish is only really problematic if it beats too many matchups. I'd say Regice is problematic in gen 4, but we can't do anything about that because we can't change its stats. Scov is, in comparison, not problematic because:
Scovillain | 50.15% | 0.858 | 41577 | 82907 |
Scovillain | 50.03% | 0.061 | 6685 | 13363 |
That is clearly not true for it. And winrates are extremely relevant because of statements like:
Majority of the time, if you have a team that's able to incapacitate a Pokémon, or (god forbid) your opponent makes the mistake of sending out something defensive, not knowing you have Scovillain, and you pivot in to Scovillain, that's the game right there. Nothing they do matters, no skill they have matters, and there is no coming back from simply having a Scovillain switch in.
"Majority of the time" stands out here because that is indeed the crux of the conversation. Every mon is capable of full sweeping the opponent depending on their team, we just don't really consider Kricketune to be a sweeper because it happens so rarely. Well, it also happens pretty rarely for Scovillain and the stats prove it.
You can argue the 50% speaks to polarisation, but that's kind of a non-argument as it wouldn't apply anywhere else. Palossand and Tornadus-Therian were the two closest to 50% last month (50.1 and 49.9 respectively) so are they more polarising than Scov? It must suck to win half the time and lose the other half with Palossand, so should we turn it into a Specs sweeper? Then it'd be far below 50%, and therefore less polarising. That's a good thing, right?
And to the point that "nothing else has the same game-ending potential just by being sent out", I respectfully disagree. Basculegion and Houndstone certainly do. Supreme Overlord Kingambit, too. My most hated mon this gen is actually Sneasler, I've been unable to stop Sneasler sweeping me just because of the team I got far more often than has happened with any other Pokémon because Sneasler is fast, strong, and has two excellent attacking moves for either Band or SD. Not to mention Barraskewda, whose entire playstyle in rands is "wait until the last minute to reveal and hope the opponent has nothing to tank one of its moves".
Take away your argument about 'the winrate is 50% so it's balanced' and ask yourself WHY the winrate is 50% and whether or not what this set adds to Random Battles is positive or negative. Both from a competitive and a fun perspective.
Rands' philosophy is, and never has been, about what's fun. The reason for that is because fun is unquantifiable. Moreover, it's also because there are no real ways to maximise fun within the restrictions that are imposed by Pokémon as a game itself. Things we've done toward increasing competitivity of the game have increased fun by most people's metrics, such as stricter generation rules when it comes to type diversity, but those aren't done for "fun" purposes. But personally I think getting paraflinched by Togekiss sucks, it isn't fun to be on the receiving end of and isn't fun to do, either, because it feels cheap. That applies to Du(du)nsparce too, and actually any mon with Waterfall or Air Slash. I lost a major tournament game a couple weeks ago because I got flinched with Waterfall twice in a row. That's not fun. But (this was in gen 4) we can't just make Bibarel use Aqua Tail instead because a 10% miss is IMO overall more fun for both players than a 20% flinch, because that would make Bibarel less consistent overall and therefore make the format less competitive. And others may disagree with that definition of fun, anyway.
tl;dr
- Bad matchups are a part of rands and they suck hard. They're also a part of Pokémon as a whole, but feel more meaningful on an emotional level because rands players don't get to make their teams themselves.
- Scovillain will always be a matchup fish regardless of what set it has. If Moody were removed it would be replaced with a sun sweeper set, which is just as much of a "this mon wins the game or it is a 5v6" set as Moody is. This is because of Scovillain's properties as provided by Game Freak, and there's nothing we can do about that.
- This is not a trait unique to Scovillain. In fact, it is a trait shared by most Pokémon. Once you've been part of major tournaments for a long time you get desensitised to it, but when I was starting out in tournaments like RBTT I used to get confused at the sack choices my opponents or team partners made, until I understood that even though that Bewear is usually an incredible mon, somehow in this particular matchup it was dead weight and Girafarig was worth preserving more.
- Stats are an important way to judge how overbearing a matchup fish is. This can be seen in other generations such as gen 4, where Regice is a very overbearing matchup fish also just as a result of its properties as provided by GameFreak. Regice is a far more annoying mon than Scov, because it autowins much more often. Not to mention something like Xerneas in gens 6 or 7, an extremely good mu fish, but that one is divisive because lots of players find it fun and lots of players (like me) hate it, and that's number 1 in the winrate in gen 7 2 months running. It can also be seen in gen 9, where Sneasler was the most overbearing mon in the format until it got successfully nerfed by levels BECAUSE of its winrate. Now it's probably just top 5 most annoying. You can argue overbearingness is irrelevant to "fun", but a matchup fish that never gets a good matchup isn't unfun for the opponent, because it almost never does anything, such as pre-webs SD Kricketune. In comparison, a mu that is disproportionately good, such as gen 5 Gorebyss, is considered unfun by most. These concepts cannot be separated, and haven't even been successfully separated in your post with respect to your phrasing, because they are so intrinsically linked.
- The idea that Scov is somehow special in its game-ending potential just as a result of being sent out is therefore not true. What is being referred to with that statement is that Scov is sent out when your (opponent's) team has nothing that can handle it -- a matchup fish -- and it can be seen in practice that that matchup fish is not special in its effectiveness, in its likelihood of being deadweight or not (Palossand is not a MU fish but is 50%, stats don't quite work out that elegantly or specifically, the stats just demonstrate that Scov isn't special in its power level), nor in its competitivity. Being about 50% is the aim of winrate-based level balancing in order to maximise competitivity, in fact.
- Making decisions in rands for "fun" is not possible. We make decisions for competitivity, under the assumption that most players deem competitivity and fun to be just about the same thing. Scov is not going to be competitive with any set, and a Chloro Sun sweeper is no more competitive in rands than Moody is, and actually probably significantly less competitive because, even if we do give it Tera Blast, it will always be hard walled by Fire- or Dragon-Type opponents, making it even more "dead weight or game winning". Both are all-or-nothing matchup fishes with roughly even game-ending potential once levels are balanced properly, with that potential dictated entirely by the opposing team. Making Scovillain bad so that it's not longer annoying is not an option, as that is uncompetitive for the player that gets a teamslot used up on it.