But like I said, it's just a proposal, and you're free to argue for Dunsparce being placed higher.
I made a case before for Dunsparce being High, although now i think Mid:
Dunsparce: - High Tier [I never thought I would say that]
Availability: Shaking Grass at Floccesy Ranch, requires 1 badge, low encounter rate
Stats: Far higher than what most pokemon at that stage of the game will have for a while, but low towards the end. Defensive lean, with massive HP, and bad speed.
Typing: Normal Typing, which is solid all around. Fighting types and fighting attacks are less common in B/W2, although there is now a major enemy in the game that uses Steel-types.
Movepool: Wide enough. Dunsparce can work in several ways. It gets several crippleing moves, such as Glare and Yawn, as well as decent offensive options. It also gets Roost for recovery. It gets most of what it needs by leveling up, and has little to no reliance on tutor moves, unless you want Aqua Tail or Zen Headbutt.
Of special note is that Dunsparce benefits tremendously from the early access to TM Return, giving Dunsparce it's most powerful non-recoil attack early in the game. It also has the Defense Curl + Rollout combination.
At level 25, when Dunsparce's bulk may start to lessen, it gains Roost. In addition, when it starts to fall off again, it picks up Coil at Level 37, which, in tandem with Roost, allows Dunsparce to quite literally sweep physically based foes. Drill Run is picked up at Level 43, allowing Dunsparce an answer to Rock and Steel types. [Although it also gets Dig at Level 31, Drill Run outclasses it, especially with the accuracy boost from Coil]
Major Battles: Dunsparce does not shine in any major battle in particular, although it can do work against Roxie and Burgh in particular because of it's high stats for that part of the game [Burgh also is weak to Rollout]. Dunsparce struggles against Corless, Marlon and Shuntal, although it holds it's own against most others unless they have ridiculous power behind their attacks, like Haxorus.
Additional Comments: Due to it's bulk and Base 100 HP, Dunsparce is a brilliant candidate for the early Leftovers. Dunsparce is the definition of a Disc 1 Nuke in B/W2, but dosen't fall off as hard as you may expect, transitioning from a powerhouse that will OHKO everything and laugh hits off, to a slower, set-up tank that still laughs at physical attackers with a set like Coil/Roost/Drill Run/Return.
Run Away is pretty good in-game for saving time from wilds. Serene Grace with Dunsparce's speed and movepool is pretty bad unless you are spamming Ancientpower.
Dunsparce is exceptionally powerful for the stage of the game you get it, with massive bulk, good offenses, and STAB Return. It can solo Roxie by stats alone, and Burgh with Rollout. It remains useful against Elesa, and can even hold it's own against Clay with it's Return and Dig.
It doesn't even fall off completely, because it gets Roost and Coil later, allowing it to set up.
It's not useless like the other Bottoms. Hell, Dunsparce is
EASILY better than Patrat and Sunkern, and they're in Low.
I wouldn't agree at all with Dunsparce being Bottom, if only because of it's potential as a Disc 1 nuke.
Dunsparce should be Low at worst, Mid at best. In my opinion, Bottom is for pokemon who are
completely useless on an in-game run. You can catch a Dunsparce and use it to power through solo to where you can get to Route 4/Resort Desert and then you can grab stuff like Scraggy and Siliglyph and Darumaka.
Dunsparce isn't even useless lategame, unlike the other bottoms.
For that matter,
Sunkern should be Bottom Tier. It's useless, you're stuck with it until Gym 4, and it has a disadvantage against Gyms 2 and 3 to boot, and you should be using that 1 Sun Stone on a Cherubi.
Speaking of,
Cherubi is either Top or High Tier. Not sure which. It destroys B/W2 even more than B/W1, because Ice Gym is gone and replaced with Water.
Solrock for Low. It comes too late to be useful, and... well... too late in the game in the first place. To put into perspective, Lapras is available about 5 mins later if you dodge trainers, and Lapras is about 5 times more useful, if harder to find. By this logic,
Lunatone for Low.
It's say
Litwick is Mid. There is no Ice Gym anymore. There is a Water Gym. That hurts. Litwick's match-ups from when you can catch it are unfavorable for the majority, except Caitlyn and Corless. [Marshall spams Rock moves]
Deerling is High Tier. It just WRECKS with a moveset of Seed Bomb/Jump Kick/Return, easily obtainable. Ice Gym Water Gym blah blah. I used a Sawsbuck once, and it just rolled faces.
Also you can get it Swords Dance if you want. Which just gets stupid.
These don't need much explanation that's not alrealy been provided.