There's literally only one problem I ever have with Talonflame, and that's a double switch to rotom-w. I switch in my counter such as heatran while they switch out talonflame and go to rotom-w. The synergy between those two is amazing. Heatran, Empoleon, Tyranitar, Kabutops, Tyrantrum, Regirock, Aggron, Slowbro, Gliscor, Landorus-t. Every pokemon I can think of as a talonflame counter gets busted by the washing machine, either water weak, electric weak, or will-o-wisp burn weak. That's the benefit of double switching of course.
I've been scrolling through the list of pokemon and trying out different ideas over the past week and I haven't been all that successful. The goal, I guess, is to counter talonflame and also be able to fight rotom-w. Do any of you have ideas? Assault Vest Tyranitar certainly works but doesn't quite hit rotom very hard, so for this particular purpose I actually suggest a scarf tyrantrum to head smash bitches.
I agree that the Talonflame+Rotom W core is really effective as they synergize well both offensively and even defensively to some extent. However, there are a few things that can be done to get around these two. Well for one, I think setting up rocks will really help as it will limit their volt-switch shenanigans. Generally, volt-turn teams don't appreciate hazards. I believe they thrive on the switches the opposing Pokemon in the team it makes due to the volt-turn team's synergy; forcing switches and whittling the opposer down in the process by constant usage of the moves. This is where they get their momentum from. Now, laying those hazards will basically discourage or limit their switching capabilities. For a team that relies mainly on constant maneuvering and switching to gain the advantage, time will take its toll and eventually whittle the volt-turn team's Pokemon down.
Apart from this, a Pokemon that can potentially do well against the core is
Mega Ampharos. Electric/Dragon walls the the type coverage the core offers resisting Flying, Fire, Water and Electric. This coupled with 90/105/110 bulk can aid in checking the them. The bulky offensive pivot may be a decent asset in keeping the core at bay. A set along the lines of Volt Switch l Dragon Pulse l Thunderbolt/Focus Blast l Thunder Wave at 178 HP / 252 SpA / 84 Spe seems good.
Some calcs:
252+ Atk Life Orb Talonflame Flare Blitz vs. 178 HP / 0 Def Ampharos: 97-116 (26.57 - 31.78%) -- possible 4HKO
252+ Atk Life Orb Talonflame Brave Bird vs. 178 HP / 0 Def Ampharos: 97-116 (26.57 - 31.78%) -- possible 4HKO
56+ SpA Rotom-W Hydro Pump vs. 178 HP / 0 SpD Ampharos: 72-85 (19.72 - 23.28%) -- possible 6HKO
56+ SpA Rotom-W Volt Switch vs. 178 HP / 0 SpD Ampharos: 21-25 (5.75 - 6.84%) -- 9HKO at best
56+ SpA Rotom-W Hidden Power Ice vs. 178 HP / 0 SpD Ampharos: 98-116 (26.84 - 31.78%) -- possible 4HKO
Quite impressive if you ask me. However, there are things to be considered that hampers Mega Ampharos's overall effectiveness. One, it might be unappealing to some that a precious slot for Mega Evolution will be given up to Mega Ampharos. Two, the Mega lacks a reliable recovery move. And three, the omnipresent stealth rocks is almost always a factor in taking into account damage inputs. With a combination of these, it is expected that Mega Ampharos will be whittled down to KO range if played recklessly. Well to remedy this, one could opt for a Rest+Talk set with Heal bell and a defensive spread or simply give the Pokemon Wish support. In the former case, its use now leans more to a walling set.