While I can see why you would use Bisharp, I do not think it is worthy of a rise. It has rough matchups against every non-balance team because of losing to common pokemon on offense such as roost tapu koko, protean greninja, ash greninja, tapu lele, swords dance bulu, and sub zygarde just to name a few. It also uses a z move and only fits on hazard stacking/sticky webs so it is a fairly niche mon overall.
It is also not as good of a balance breaker as you claim it is. It needs to take chip damage if it wants to set up on Ferrothorn or Clefable. This keeps it in range of common balance mons like Swords Dance Gliscor, and Bulky Zapdos. It also loses to common Substitute users like Metronome Mamoswine and Zygarde which can be seen on balance. It loses to most unchipped Zygarde sets too. In addition, rising sets such as Will O Wisp Heatran and Heat Wave helmet torn keep immense pressure on it. Ash-Greninja, Roost Tapu Koko, Hawlucha, Keldeo, Protean Greninja, Shift Gear Magearna, Swords Dance Tapu Bulu, and Tapu Lele can all be seen on balance builds and all prevent Bisharp from truly sweeping. Even a matchup where Bisharp is amazing, it can lose to a competent player who scouts for the Z Move and minimizes its set up oppurtunities. While you accepted that it is a risky pokemon, if it is your sole balance breaker, you can be at a major disadvantage and a competent player can beat it in a difficult matchup.
The pokemon faces immense competition from Mega Mawile. Mega Mawile is far more consistent than Bisharp, and even in a hard matchup, Mega Mawile can use its far higher initial breaking power. Mawile also helps a lot against stall, does not use a z move, does not struggle immensely against offensive teams, and can prove its worth in a non-super good matchup while winning in a good one. It has far more set up oppurtunities thanks to its better bulk, typing, and intimidate as a pre mega ability allows it to set up on locked greninja, CB Kartana, Clefable, Tangrowth, and much more. Bisharp does not need chip against Landorus-T and can blow past Celesteela and Curse Scizor if it predicts right, though.
Saying that, I feel as if Bisharp does not deserve to be ranked with the likes of Mega Heracross, Tapu Fini, and Amoonguss which are far more consistent and are not nearly as shadowed. It should be ranked with the likes of pokemon such as Mega Charizard Y, which is also a pokemon that matchup fishes, but can somewhat alleviate poor matchups with Magma Storm Heatran support.
----> A
Magearna has taken a few hits over the last couple of months. Assault Vest Magearna is the main set that has been hurt as it is nowehere near as consistent as it was. In a metagame where Zygarde and Heatran are borderline broken and Gastrodon is as good as ever, which saps magearna's greatest asset in gaining momentum, and therefore Vest Magearna struggles to justify itself over a grass type. While it is a solidder Lele check, it can get whittled down extremely quickly and therefore is only really used on offense. Offense is considerably worse when balance is the best archetype in SM OU by far and Magearna has been used less for Heatran on Medicham offense because Magearna's job of gaining momentum has become much harder. Magearna is forced to run Ice Beam to not lose to Gliscor, which removes most of its offensive utility and prevents it from pressuring breakers like Medicham and Kyurem-Black. It is also strapped for slots which prevents it from carrying Energy Ball to hit Gastrodon as without Iron Head it loses to CM Lele and cannot remotely pressure fairies in general and even Pokemon such as Weavile and Tyranitar. HP Fire is a move that simply should never be replaced with Ferro and Scizor stacking up hazards or boosting up on it freely.
Shift Gear Magearna, while still a good set deserves the same rank as good Pokemon such as Gliscor(will be A probably) and of Protean Greninja and not the rank of Pokemon like Ferrothorn, Zygarde, and Ash-Greninja as Shift Gear Magearna needs Fairum CM to beat Gastrodon and loses to Toxapex, while needs to use the Z Move at the right time. If it calm minds onto a Heatran, Zygarde or Gliscor switch, predicting Gastrodon, it loses momentum quickly. It needs chip on common mons like Ferrothorn, Heatran, and Celesteela to beat them. It is also reliant on hitting Focus Blast's to steamroll when considerably ahead. That said, Shift Gear Magearna is an extremely potent wincon which can beat many unprepared teams with the right set, but it is not an A+ rank set.
I can safely say I disagree with most of what is in this post.
but lets take it one step at a time: First off, your comparison with mega mawile
you say that mega mawile has is "far more consistent than bisharp," and yet you say that bisharp struggles against all these common pokemon
It has rough matchups against every non-balance team because of losing to common pokemon on offense such as roost tapu koko, protean greninja, ash greninja, tapu lele, swords dance bulu, and sub zygarde just to name a few.
How is mega mawile any different? Isn't the Play rough/SD/sucker punch/knock off set that supposedly outclasses bisharp also have trouble with all of these pokemon commonly found on offense? How is bisharp much different, aside from dying to a speedy superpower bulu? And even then mega mawile is far from safe considering things like cb wood hammer or z-wood hammer, getting killed by both of those after just ~20% chip.
I mean almost every flaw you call bisharp out on also applies to mega mawile (gets pressured by wisp tran, zapdos, gliscor) and almost every boon you say mawile has also applies to bisharp (sets up on choice locked gren, cb kartana (just not locked into fighting move), clefable, tangrowth, and "much more.")
Not to mention Bisharp has this fantastic ability called DEFIANT, which mega mawile does not! This ability can punish defog, punish webs, and even punish smaller things like moonblast, making it a very real risk to even attack with clefable when bisharp is on the opposing side (funny that you mention bisharp must take chip damage to set up on clefable as well) This clearly separates bisharp from mawile, and it is not as outclassed as you believe it to be. That is WHY it fits into hazard stacking/webs teams in the first place as you so eloquently pointed out.
And finally, Bisharp is being nommed up to B-, and I honestly think mons like tapu fini, jirachi, and hippo belong in B just for the rankings to be consistent. Mega Mawile is A-. That is a huge difference, and obviously bisharp is worse than mega mawile. Bisharp is just fine in B- for being a high risk, high reward pokemon that fits into webs and hazard setting styles.
Speaking of which:
While you accepted that it is a risky pokemon, if it is your sole balance breaker, you can be at a major disadvantage and a competent player can beat it in a difficult matchup.
only fits on hazard stacking/sticky webs so it is a fairly niche mon overall.
Well yeah, no shit. hazard stack/webs teams are going to have more balance breakers than just bisharp.
Judging from all these points you made, especially the last one, I just feel like you've never actually built with and used bisharp before.
So now to move on to why your magearna nomination is flawed as well.
I first of all am confused as to why the rise in zygarde and heatran (which have had consistent usage for months now, no real rise here) is suddenly a bad thing for magearna. None of these pokemon are safe switch-ins, hell, neither of these are even gauranteed to 1v1 magearna. Non-cb zygarde or groundium-z wont ohko with thousand arrows and will die to offensive ice beam, and Max hp/max speed heatran won't kill magearna after rocks gauranteed and will die to z-focus blast.
But more importantly, this little gem
and therefore Vest Magearna struggles to justify itself over a grass type.
How the hell is vest magearna doing what grass types are used to do? Aside from baaarely ferrothorn, no other grass type is put on a team to check pokemon like mega alakazam, mega latios, tapu lele, protean greninja, ash greninja, kyu-b, torn-t, weavile and probably more shit i'm missing all in one slot. From a teambuilding perspective, it is honestly ludicrous to think that av magearna faces competition from grass types.
The rest of your post goes into detail about how magearna is supposedly strapped for moveslots, and you explain that magearna needs all of these moves to hit all of these potential checks. But what confuses me is why is this a bad thing?
I mean, isn't it a very, very good thing that magearna can pick and choose what it beats? Why are you punishing magearna for its versatility? It's not as if it REQUIRES all 7 moves it could run in order to properly function, it can bring fleur cannon/volt switch for AV sets and leave the last 2 open for whatever the team can't do. I think that you're looking at this in a vacuum, and you're failing to notice that any supposed trouble or weaknesses that magearna has can simply be moved around by whatever moves it decides to run. The fact of the matter is that magearna can work around almost all of its supposed checks, and only very niche pokemon like jirachi can really claim to wall magearna, and thats not even stopping volt switch.
You also mention how it needs chip on common mons like ferro, tran, and steela, but yeah, what cleaner doesn't? Do you expect ANY late-game sweeper to be blasting through its checks at full health? Even your precious zygarde needs chip on common mons like clefable, lando-t, tapu bulu, and tangrowth to be cleanly sweeping with standard dd z-move sets, and WP dd doesn't break past other checks like healthy mew or curse mzor.
Yes, zygarde doesn't have any counters either, but thats because it can CHOOOOOSE what it wants to beat!! Much like Shift Gear Magearna!! You dont see people shitting on subtoxic zygarde for failing to break through clefable, because they also know that WP destroys it! You dont see people calling dd z-thousand arrows zygarde ass for getting stopped by av tangrowth because they also know that dd z-outrage blows that same mon the fuck back. So why are you saying SG magearna is bad? So what if heatran beats calm mind? Z-focus blast kills that! So what if pex walls Z-fairium, Z-tbolt kills that! Even chansey can be overwhelmed by some heat sets like cm+pain split, because if that's what you want magearna to do, then fuck it, it CAN.
The ability to pick and choose which pokemon checks you and have your team handle the rest is what being versatile IS. And I think it's absolutely silly to be punishing magearna for that.
Keep magearna A+, and raise Bisharp to B-
Apologies for the essay