Alright, here's the laundry list:
Banette - S/A+ Rank: Banette is easily one of the most dangerous threats in the tier, and is a possible candidate for S-Rank. I'll be copying another post of mine: Mega-Banette is one of the most versatile pokemon in the tier. With Prankster, a large support movepool, and a sky-high base 165 attack, Banette can run a variety of different sets ranging from offensive to support. With Prankster Destiny Bond, Banette acts as an amazing "fail safe" for virtually all types of teams. Venomoth passed a Quiver Dance to Moltres and is wrecking your team? A Sharpedo that you just can't seem to stop? Send in Banette, and save your team from a certain sweep. Banette is the ultimate insurance for a team. Also, with access to Prankster Taunt, it can easily shut down many walls and setup sweepers, and greatly eases prediction with Sucker Punch and Destiny Bond. However, unlike many other support pokemon, Banette has the unique trait of being a considerable offensive threat to your opponents. With a base 165 attack, Banette can put large dents in the opposing team. Plus, with a strong priority move like Sucker Punch, Banette can KO many threats without sacrificing itself with Destiny Bond.
This, plus the fact that it can run a large variety of other sets, like Will-O-Wisp or SubDisable, make Banette extremely unpredictable. Banette fills almost all the criteria for an S-Rank poke: It easily creates free-turns with Prankster Taunt and the threat of a Destiny Bond or Sucker Punch, can run circles around most, if not all of the metagame with its Taunt + Sucker Punch/D-Bond/Shadow Claw shenanigans, and can preform a large number of roles effectively. Furthermore, it has no true counters, as almost everything can be taken down with Destiny Bond. The only time when Banette will fail to do its job is a mispredict or if its inflicted with Toxic/Burn.
Sceptile - A-/B+ Rank: With all the new additions to the tier, Sceptile is just not what it used to be last gen. Despite its amazing speed tier, it often hits disappointingly soft with its rather modest Special Attack. Plus, it is extremely reliant on which Hidden Power it carries, being walled by Moltres and Delphox if it runs Fire, and Amoonguss and Escavalier if it runs Rock. Moreover, its Swords Dance set is almost entirely outclassed by Virizion, especially now with the loss of the Flying Gem. However, don't get me wrong - it is still an amazing late game cleaner with its blistering speed, but is not worthy of an A rank.
Braviary - B+ Rank: Choice Scarf Braviary is a fantastic late-game cleaner and revenge killer in general. Brave Bird of off a base 123 attack hits extremely hard, 2HKOing everything not significantly invested into bulk or resisting it. Plus, it fits amazingly on hazard-stacking teams due to it being the only viable Defiant user in the tier.
Amoonguss - B+ Rank: This thing can wall a large number of significant threats, notably Hitmonlee and Virizion, and makes for a great pivot. Spore is still a devastating move, and most of the things immune to it are walled by Amoonguss, like Tangrowth, Virizion, and Sceptile.
Bronzong - C+ Rank: While Bronzong does have great mixed defenses, it often does not pull its weight in most matches. Stealth Rock support is nice, but Bronzong doesn't really bring anything to the table, and is easily KOed to its lack of reliable recovery. It just doesn't hit hard enough, and is really not going to be doing anything major throughout matches. It is complete setup bait for virtually all sweepers, and cannot do anything back besides chip away with its weak attacking moves or Toxic.
Clawitzer - B+/B Rank: I honestly have no idea what Clawitzer is doing down in C rank. With its great Special Attack and wide coverage, it can punch serious holes in anything that tries to switch in. Sure, it's low speed holds it back, but Clawitzer's wallbreaking potential cannot be denied.
Shuckle - B+ Rank: Though this thing is fairly one-dimensional, it is undoubtedly the best at its role, for reasons already discussed. The sole fact that it faces almost no competition is definitely enough to warrant it a B+ rank.
Vivillon - A- Rank: If you switch this in at the right moment, it could as well mean good game for your opponent. Sleep Powder almost guarantees at least one Quiver Dance against slower pokemon, and a 91% STAB Hurricane at +1 absolutely destroys things not significantly invested into special defense. Of course, it still needs support, notably things like Rhyperior removed, but its almost unparalleled sweeping potential makes this thing a top threat.
Claydol - D/E Rank: This thing definitely should go lower, as it is almost completely eclipsed by every spinner. It's only real niche is access to Stealth Rocks and Rapid Spin, but its pitifully weak offensive presence just makes it dead weight 90% of the time.
Rotom-S - B-/C+ Rank: I realized that Rotom-S wasn't ranked, and is definitely viable in RU. It's good bulk, good typing, and access to Will-O-Wisp makes it a great burn spreader, and walls a significant amount of important threats like Escavalier and Cobalion.
Skuntank - B/B- Rank: While Skuntank might face competition from the likes of Gligar and Golbat, it is still very good at what it does - Defog. Its many unique traits such as access to Sucker Punch and a great CM Cress/Reuni counter merits its use on many teams.
Kabutops - B+ Rank: I definitely agree with this, as Kabutops is arguably the best offensive rapid spinner in the tier (unless if you count Hitmonlee as a spinner), being the only spinner capable of significantly threatening spinblockers. Plus, it is the only spinner capable of functioning completely effectively outside of its role as a spinner, bar Hitmonlee.
Banette - S/A+ Rank: Banette is easily one of the most dangerous threats in the tier, and is a possible candidate for S-Rank. I'll be copying another post of mine: Mega-Banette is one of the most versatile pokemon in the tier. With Prankster, a large support movepool, and a sky-high base 165 attack, Banette can run a variety of different sets ranging from offensive to support. With Prankster Destiny Bond, Banette acts as an amazing "fail safe" for virtually all types of teams. Venomoth passed a Quiver Dance to Moltres and is wrecking your team? A Sharpedo that you just can't seem to stop? Send in Banette, and save your team from a certain sweep. Banette is the ultimate insurance for a team. Also, with access to Prankster Taunt, it can easily shut down many walls and setup sweepers, and greatly eases prediction with Sucker Punch and Destiny Bond. However, unlike many other support pokemon, Banette has the unique trait of being a considerable offensive threat to your opponents. With a base 165 attack, Banette can put large dents in the opposing team. Plus, with a strong priority move like Sucker Punch, Banette can KO many threats without sacrificing itself with Destiny Bond.
This, plus the fact that it can run a large variety of other sets, like Will-O-Wisp or SubDisable, make Banette extremely unpredictable. Banette fills almost all the criteria for an S-Rank poke: It easily creates free-turns with Prankster Taunt and the threat of a Destiny Bond or Sucker Punch, can run circles around most, if not all of the metagame with its Taunt + Sucker Punch/D-Bond/Shadow Claw shenanigans, and can preform a large number of roles effectively. Furthermore, it has no true counters, as almost everything can be taken down with Destiny Bond. The only time when Banette will fail to do its job is a mispredict or if its inflicted with Toxic/Burn.
Sceptile - A-/B+ Rank: With all the new additions to the tier, Sceptile is just not what it used to be last gen. Despite its amazing speed tier, it often hits disappointingly soft with its rather modest Special Attack. Plus, it is extremely reliant on which Hidden Power it carries, being walled by Moltres and Delphox if it runs Fire, and Amoonguss and Escavalier if it runs Rock. Moreover, its Swords Dance set is almost entirely outclassed by Virizion, especially now with the loss of the Flying Gem. However, don't get me wrong - it is still an amazing late game cleaner with its blistering speed, but is not worthy of an A rank.
Braviary - B+ Rank: Choice Scarf Braviary is a fantastic late-game cleaner and revenge killer in general. Brave Bird of off a base 123 attack hits extremely hard, 2HKOing everything not significantly invested into bulk or resisting it. Plus, it fits amazingly on hazard-stacking teams due to it being the only viable Defiant user in the tier.
Amoonguss - B+ Rank: This thing can wall a large number of significant threats, notably Hitmonlee and Virizion, and makes for a great pivot. Spore is still a devastating move, and most of the things immune to it are walled by Amoonguss, like Tangrowth, Virizion, and Sceptile.
Bronzong - C+ Rank: While Bronzong does have great mixed defenses, it often does not pull its weight in most matches. Stealth Rock support is nice, but Bronzong doesn't really bring anything to the table, and is easily KOed to its lack of reliable recovery. It just doesn't hit hard enough, and is really not going to be doing anything major throughout matches. It is complete setup bait for virtually all sweepers, and cannot do anything back besides chip away with its weak attacking moves or Toxic.
Clawitzer - B+/B Rank: I honestly have no idea what Clawitzer is doing down in C rank. With its great Special Attack and wide coverage, it can punch serious holes in anything that tries to switch in. Sure, it's low speed holds it back, but Clawitzer's wallbreaking potential cannot be denied.
Shuckle - B+ Rank: Though this thing is fairly one-dimensional, it is undoubtedly the best at its role, for reasons already discussed. The sole fact that it faces almost no competition is definitely enough to warrant it a B+ rank.
Vivillon - A- Rank: If you switch this in at the right moment, it could as well mean good game for your opponent. Sleep Powder almost guarantees at least one Quiver Dance against slower pokemon, and a 91% STAB Hurricane at +1 absolutely destroys things not significantly invested into special defense. Of course, it still needs support, notably things like Rhyperior removed, but its almost unparalleled sweeping potential makes this thing a top threat.
Claydol - D/E Rank: This thing definitely should go lower, as it is almost completely eclipsed by every spinner. It's only real niche is access to Stealth Rocks and Rapid Spin, but its pitifully weak offensive presence just makes it dead weight 90% of the time.
Rotom-S - B-/C+ Rank: I realized that Rotom-S wasn't ranked, and is definitely viable in RU. It's good bulk, good typing, and access to Will-O-Wisp makes it a great burn spreader, and walls a significant amount of important threats like Escavalier and Cobalion.
Skuntank - B/B- Rank: While Skuntank might face competition from the likes of Gligar and Golbat, it is still very good at what it does - Defog. Its many unique traits such as access to Sucker Punch and a great CM Cress/Reuni counter merits its use on many teams.
Kabutops - B+ Rank: I definitely agree with this, as Kabutops is arguably the best offensive rapid spinner in the tier (unless if you count Hitmonlee as a spinner), being the only spinner capable of significantly threatening spinblockers. Plus, it is the only spinner capable of functioning completely effectively outside of its role as a spinner, bar Hitmonlee.
