Kaizo, I have to disagree with you about Conkeldurr. Tornadus-T may be gone but Conkeldurr is still ruined by Rain. Starmie, Thundurus-T, Tornadus-I, Keldeo, and even Specs Politoed blow Conkeldurr away and its most common set lack the punch it needs to keep most of them from switching in before he's set up. Rain is just such an overly-powerful playstyle that Conkeldurr just can't stand up to it and none of their sweepers really care about Mach punch so he's not even useful for that angle. Conkeldurr does do fairly well against Sand and Balance. Most teams use Landorus-T or Gliscor as their sure-fire Fighting-type check and Bulk Up Conkeldurr just runs through them has nothing to fear from Physical Dragons after a Bulk Up or two. Sun and hyper offense are big issues as well but not nearly as much as Rain is.
Like most of C-Tier, Conkeldurr's usefulness is very situational. B-Tier Pokemon aren't perfect, but they serve a function that is useful against any team. Conk shouldn't be any higher than C-Tier.
But on the subject of C-Tier Fighting-types, I'd like to nominate
Heracross for B-Tier. Scarf Heracross is very much C-Tier but Choice Band Heracross is
B-tier with no question in my mind. I've been working with it for a few months now with great success.
Heracross has resistances any other Fighting-type would kill for including Terrakion (Fighting & Ground mostly,) Base 125 Attack and Guts, Solid Defenses 80/75/95, and 85 Base Speed. It's STAB coverage can seem a bit redundant with them both being resisted by Poison, Flying, and Ghost but there are so few resistant Pokemon that aren't 2HKOed by its STAB move that it's a non-issue. CB Heracross has only 2 true counters in OU: Landorus-T and Gliscor. Nidoqueen can stop it too she's not common by any stretch and Tentacruel absolutely needs Rain to stand a chance (and even then, Stone Edge nails it.) Any Ghosts that aren't 2HKOed by Megahorn are beat by Shadow Claw. For reference, this is Heracross' damage calcs on Pokemon relevant to OU:
Notice how Skarm and Forretress aren't even on the list (they take 52.82 - 62.71% from CC with Max Def) and notice how much Tentacruel takes from a resisted Close Combat/Megahorn. Heracross is just that powerful. It preys on defensive Pokemon like Ferrothorn because it can either run them over or OHKO/2HKO are switch-in. Even a bad prediction on Heracross' end can be deadly. For example, Sandard Jellicent takes 49.25 - 58.16% from Megahorn, a clean 2HKO after SR. If the opponent lacks one of the 3 or 4 Pokemon that can actually come in on Heracross, you can often click Megahorn and watch something die. It even preys on Politoed because Heracross is bulky enough to take a Scarf Hydro Pump and is faster than Spec so Hera can just OHKO Politoed turn one with no risk at all. It's even one of the few Pokemon that makes Deoxys-D shit itself turn one. Rain still threatens it since, while it's defenses are solid, they're nothing amazing. But unlike Conkeldurr or even Virizion, Heracross is anything but an open invitation for rain sweepers. All of Rain's top sweepers are OHKOed on switch depending on the move and 2HKOed at the very worst. And best of all, it has Guts. Scald and Will-O-Wisp are liabilities around Heracross and the same goes for Ferrothorn's T-Wave and Tenta's T-Spikes. Even Breloom can't really threaten it because Heracross can easily run Sleep Talk at the cost of Shadow Claw (Which only matters for Dusclops and Cofagrigus tbh.)
It's a nasty Pokemon to face down once it's counters are dealt with and I think C-tier is just selling it too short as it is very much in the same league as Hydriegon. If it's not smashing apart teams, it's breaking down core Pokemon to allow a teammate to sweep unhindered.
