Alright man you are contradicting yourself now, first you say Darmanitan is C b/c he has way too low speed, and now you are saying 50 speed is enough to wallbreak, PLS restrain to one reason at the very least, I have argued that 95 speed is enough to wallbreak and you said "wtf no it is not" and then "Mega mawile has enough speed to wallbreak" and you don't stop there, you also say "Conkeldurr has enough speed to wallbreak" ok, you are making 0 sense now.Let's compare Darmanitan to the wallbreakers of the A and S ranks.
1. Mixed Aegislash
Much higher bulk, much better typing, higher base Attack and Special attack, has priority, less speed but the difference is negligible because in this meta it's practically >100 or gfto
2. Mixed MegaChomp
Much better bulk, much better mixed attacking stats, practically identical speed, takes up mega slot
3. CB Azumarill
Much better bulk, much better typing, hits like a train wreck, has priority, neglibigle speed difference for the same reason as Aegislash
4. ZardY
much better nuke in general but has a bad SR weakness and takes up the mega slot
5. Mega Mawile
better bulk, highest base attack in the game after factoring in Huge Power, one of the best typings, has strong priority, takes up mega slot, slower but that still doesn't matter for wallbreakers
6. Kyurem-B
Higher base attack stat, higher special attack, much better bulk, same speed, SR weakness, poor physical movepool
7. Mega Medicham
100% better than darmanitan except it takes up the mega slot
8. Conkeldurr
same attack stat and also has sheer force, much better bulk, one of the best AV users, does everything darmanitan can but with even more viable options except it is a lot slower but, finally, that doesn't matter too much for wallbreakers
As you can see, it is completely eclipsed by pokemon in the higher ranks. If all those pokemon had much less reasons why it's overall better than darmanitan, then it could be a B but it when compared to the pokemon of the higer ranks it only has one maybe two slight advantages over them, while they completely outclass it at everything else. That is why Darmanitan is a C. Plz dude, this argument should not have lasted this long. Can we please argue about something else like maybe a ranking for Mega Abomasnow?
And please don't bring up goddamn scarf Darmanitan because I really don't want to make all of the comparisons to show you why you're wrong again.
Ok that's one, and now two: The pokemons you mentioned DO outclass Darmanitan, but you have provided no true evidence, you lacked legit reasoning, and sometimes your reasoning was wrong.
First, Mega Medicham does outclass Darmanitan, but just saying that is not evidence.
252 Atk Life Orb Sheer Force Darmanitan Flare Blitz vs. 4 HP / 0 Def Cryogonal: 1718-2022 (609.2 - 717%) -- guaranteed OHKO
252 Atk Pure Power Mega Medicham High Jump Kick vs. 4 HP / 0 Def Cryogonal: 1736-2046 (615.6 - 725.5%) -- guaranteed OHKO
Life Orb Jolly Darmanitan is doing a bit less, FB has less recoil than HJK, but Mega Medicham has more speed, coverage, etc. so Mega medicham does outclass, but not just flat out "outclass 100%"
and Mega Char Y isn't a "Much better nuke"
252 SpA Mega Charizard Y Fire Blast vs. 252 HP / 0 SpD Abomasnow (I made Abomsnow have Equal SpD to Def) in Sun: 1596-1876 (415.6 - 488.5%) -- guaranteed OHKO
252 Atk Life Orb Sheer Force Darmanitan Flare Blitz vs. 252 HP / 0 Def Abomasnow: 1778-2095 (463 - 545.5%) -- guaranteed OHKO
Mega Char Y outclasses it b/c it has MUCH better coverage and better speed.
And I could go on forever, but I want to point out my third thing: You compared it to rank A & S, exactly why I'm putting it on B-