Rampardos is crazy strong. Like, significantly stronger than Tyranitar. Given Rampardos's speed, it obviously won't be plowing through an entire team. See where I'm going?
This is a bad comparison and you know it.. Sylveon still has usable Special bulk and defensive typing, and holds a niche of not taking a Mega slot compared to its competition. Rampardos has bad bulk to go along with its bad speed, and has no Dark typing to smack OU's common Psychic types like Tyranitar; Tyranitar hits hard enough to get the OHKOs and 2HKOs it needs, and has high bulk to go along with it, meaning TTar outclasses Rampardos in literally every set.
Fairy coverage is good, but it's also very prepared for. Heavily offensive teams struggle to switch into Hyper Voice, but other than that it's not hard to just switch Ferrothorn, Heatran or Mega Venusaur into Sylveon and set up your rocks or sludge bomb shit. The fact that Sylveon can't use HP Fire and HP Ground on the same set also bites it in the ass. It has severe coverage problems.
Okay, good, you have a bulky Steel-type that Sylveon doesn't have the right coverage for. Now let's either switch it in and get it worn down by taking multiple Hyper Voices and lack of recovery, switch it in on a Baton Pass that grants the Sylveon trainer momentum, meaning your switch was most likely useless, or switch into an easy double switch for your opponent because you most likely have only one Pokemon that can answer it, forcing your hand. Or predict that switch and have one of your mons bopped by Hyper Voice.
Poison types can't switch in, Psyshock.
Again, the fact that Sylveon can't use HP Fire and Ground on the same moveset is just bad, else it'd probably be deserving of B-.
As I said above, if you have a team with, say, Heatran + Ferro, one will get lured if the opponent plays smart, meaning you have your hand forced when Sylveon is out on the field, which can be easily taken advantage of.
Thing is that Klefki also works well with most of the stuff in C+. Conkeldurr + Klefki is a good core too, since Klefki can shut down fairies for Conk and paralyze stuff. CB Staraptor also appreciates Klefki's ability to shut down stuff like Mega Lop and Weavile. Nidoking too. Don't see how this is a relevant argument tbh.
His argument was "it doesn't need to do everything, team members exist". Klef was just his example of choice.
The main problem is, what are this set's advantages over Mega Gardy? Hits harder, has higher special bulk, Baton Pass and umm... that's it. And it doesn't take up a mega. Mega Gardy doesn't even need to switch moves and has access to Focus Miss. It just has much better coverage and utility options against stuff who cockblock Sylveon.
Yup, you got everything right here. Which is why M-Gard is A and Sylveon is B-.
Baton Pass is one of Specs Sylveon's key traits that help it float in C or something, not in B-. It's just not as good as AV Meta, Entei, Rhyperior or Staraptor in my opinion.
meta should move up in the first place, Rhyp is only in C+ due to competition with Landog + Chomp, though I agree with Entei. Not sure about the rest of C+. And BP is not the only thing helping it float, you admitted to it yourself above.
It has always had severe competition, but nowadays the stuff in C+ seem to have more defined niches, which really hurts Sylveon. It's only there to spam Specs Hyper Voice, maybe lure one or two threats and scout. That's all it does. Defensive sets are outclassed by Clefable.
And that's all it needs to do, just like M-Gard. M-Gard can just afford to spam Hyper Voice more than Sylveon.
Sylveon outclasses Clefable as a Specially Defensive wishpassing + cleric Fairy-type. Not much but it at least deserves a mention.
Yeah, because Mega Venu/Scizor, Ferro, Heatran, Jirachi, Chansey and Klefki don't exist?
mvenu only wins if it gets a free switch + if its offensive, or if Sylveon is locked into a move not called Psyshock.
Scizor, ferro, jirachi, klefki are hit by HP Fire
Heatran, Jirachi, non-Magnet Rise Klefki are hit by HP Ground
At least Sylveon can potentially get through its checks and counters, unlike Staraptor, who just dies.
Yes, it can't run HP Ground + HP Fire, but honestly it doesn't need to.