Heatran can still beat it any day of the week, and, despite your post...Talonflame...can *ALWAYS* check it
Can't disagree with this, running HP Ground just for Heatran would be far too niche and the only answer it has to Talonflame is hitting it on the switch, as Brave Bird means it needs to switch or die. HOWEVER, Volcarona doesn't even need spatk investment to potentially OHKO anything but the specially defensive bulk up set on the switch.
Crawdaunt...and Azumarill
252+ Atk Life Orb Adaptability Crawdaunt Aqua Jet vs. 248 HP / 252 Def Volcarona: 244-291 (65.4 - 78%) -- guaranteed 2HKO after Leftovers recovery
8+ SpA Volcarona Giga Drain vs. 4 HP / 0 SpD Crawdaunt: 248-294 (92.5 - 109.7%) -- 56.3% chance to OHKO
At minimum Volcarona's healing back about 33% HP from that as well, and Life Orb recoil ensures the KO in the above scenario; Choice Banded is scarier as a bad damage roll forces Volcarona out the next turn, but by the same token Flame Body can burn Crawdaunt in return and finish it off anyway. At any rate I only see Volcarona on the bad end of the matchup if it's against a Banded one, and even then it's a coinflip that can be swayed in Volc's favor with more spatk investment than I'm running.
Volcarona doesn't win against Azumarill in a neutral scenario, I will concede that. It has no business switching in after a Quiver Dance or two, is the point I was attempting to make before. Against a Volcarona that hasn't set up it's definitely a check.
Additionally, even with HP Rock it can't do anything to weaknite first turn, and weaknite retaliates with +2 Attack (after weakness policy on the HP rock) earthquake.
Yeah, Dragonite's just a bad matchup overall. For what it's worth Dragon Claw hits harder than EQ (41 - 48.2% vs 33.7 - 39.9% at +0). As an aside it can't switch in on +2 HP Rock through stealth rock, but I'm aware of how shaky the argument of magical free setup turns and convenient hazards are.
Other pokemon, like Deo-S, are in OU and can also check it.
I'm not well-versed on what Deo-S does beyond hazards, taunt, and psycho boost, so I assume you're suggesting it either revenges or prevents setup and then places rocks. Every time I've run into this matchup it's usually been in a lead situation where I bug buzz in response to the predicted taunt then finish off with fiery dance if it was sashed while they place rocks, though I will concede that no speed/spdef boosts does mean I'm usually forced out by the next 'mon. Looking at the December usage stats I'm not seeing anything more threatening it could do.
Many pokemon are running rock coverage to hit talonflame (ancientpower heatran, HP Rock Rotom-W, etc.), making it an even weaker option due to it's ability to be suprise KOd.
What purpose does Rotom-W have running HP Rock when both of its STABs already hit Talonflame SE? Ancientpower is really low on usage for Heatran as well (
6.771%), though we've already established Volcarona's not winning that matchup anyway.
Goodra was introduced too, which gives another option which walls it to hell and back
The irony is, specially-based Goodra is one of the things that gives Volcarona the opportunity to set up in the first place, thanks to Volcarona being naturally faster and Quiver Dance boosting spdef to the point where leftovers are enough to sustain it against STAB dragon pulses. Physical Goodra destroys it though.
There's certainly threats that need to be removed before Volcarona can do its job, but overall I don't think it has as hard a time getting going as you think. Physically defensive sets let it set up on plenty of 'mons and it takes non-rock/flying hits like a champ. I'm still thinking
A-/B+.