As usual, I avoided conventional thinking and went in my own direction. From my experiments, I found this:
Charizard @ Charizardite X
Ability: Blaze
EVs: 80 HP / 252 Atk / 176 Spd
Jolly Nature
- Flare Blitz
- Dragon Claw
- Will-O-Wisp
- Roost
Sorry Dragon Dance lovers, but this is amazing. There isn't one Pokemon that's happy at the prospect of switching in to this, yet Charizard itself can switch in relatively easily. I mean, this moveset makes Grass/Ghost Pokemon cry, and beats all Rotom appliances after Mega evolving (it can stall out Hydro Pump, or Roost until it misses). Will-O-Wisp beats Gyarados 1v1, cripples incoming Pokemon (sup Azumarill? hi Tyranitar!), and trolls King's Shield. Dragon Claw is your main attack, while Flare Blitz should be used sparingly due to recoil (however, it's a constant threat to your opponent). Tip; use Will-O-Wisp against Skarmory, or Sturdy/Roost will compromise Charizard. Similarly, it's a good idea to Will-O-Wisp against Ferrothorn (especially if it happens to hold Rocky Helmet). The speed is to outrun Lucario before it can Mega evolve. More HP (and/or Speed) with less Attack is also viable.
This is a 359 Attack, 308 Speed, dual STAB physical Pokemon with excellent two move coverage; that's immune to burn, bulkier than you think (with an answer to all of its counters), and packing pseudo-Life Orb without recoil. Fear it.
Edit: obviously Heatran will stop this when it becomes available, but currently I've actually had most trouble dealing with Mega Venusaur (lol). When used well, Charizard is very often MVP.