This Pokemon isn't that good anymore, it still beats like a lot of teams but it literally loses to all 4 S rank Pokemon, which is never a good thing. It also really hates Braviary and Vileplume, which are also decently common with the recent meta additions. Scarf Scyther, Medicham, Hitmonlee, and almost every other scarfer after some chip revenge kills, so I don't really see the issue with dropping it to A-. I think it's a fine rank, considering that it's checks have increased in usage, but it still does it's job against bulkier teams.
That's all I have for now, if I see something that I think should change, I'll post in the future.
Roost Vikavolt Bulky Offense from Hootie - This team still struggles a decent bit with Virizion, as no Pokemon can comfortably switch in, and Virizion can benefit from setup opportunities on a few Pokemon. It's forced to rely on revenge killing to take out Virizion.
Frolass HO from Jarii - You would think this team would have a more favorable matchup vs Virizion, however it again relies on revenge killing from Froslass or Dodrio, both of which are easy to wear down. It can gain setup opportunities vs Rotom-C and Samurott, or a Dodrio locked into Jump Kick or Brave Bird.
Sub Vivillon HO from -Davon - This team matches up a bit better vs Virizion, but even then, Virizion is capable of revenge killing a few Pokemon on this team, and it's only reliable ways of revenge killing Virizion are Mesprit and Braviary, both of which are easily worn down.
Hail Offense from Z+V - Virizion OHKOs or 2HKOs this entire team basically, and if Hail isn't up, you're forced to revenge kill Virizion with Vanilluxe. Another pretty poor matchup.
Granbull Balance from neomon - This is probably the sample team with the best matchup vs Virizion, considering it has Delphox and especially Granbull as two very solid checks. However Virizion still poses as a pretty big threat for at least half of the team here.
Again, these teams are a bit outdated, but the point I wanted to get across is that Virizion is still a very potent threat in the metagame due to it's ability to find setup opportunities with ease and fare well vs any playstyle.
As for my own nomination, I think Altaria should be moved up to B+. Since the addition of Defog in Altaria's movepool, it has become an elite Defogger thanks to it's ability to match up well vs the tier's top Stealth Rockers. Steelix, Seismitoad, and Druddigon have proven to be the tier's best Stealth Rockers, and unless Druddigon is an offensive variant, Altaria can pretty handily take on all 3 and keep hazards off of it's side of the field. It's also a very solid check to Pokemon such as Emboar and Delphox (without Z-Dazzling Gleam), as well as other setup sweepers such as Slowbro and Samurott. Altaria is very splashable, can fill a lot of roles in a team, and can pivot in and out of status moves thanks to Natural Cure. Therefore I think it should rise to B+.