#1 - 2012/05/31 01:14:00 AMFire Mage PvP in Cataclysm is about high mobility, mixed with heavy damage and frequent impact procs for stuns. In Mists of Pandaria this has changed quite a bit.
You can still play a scorch-spam mage, and I'm certain many players will but the lack of impact stuns is likely to force a new play-style for fire mages.
Frostfire Bolt is still usable by fire mages, and still applies a 40% slow and counts as a non-periodic fire spell toward Hot Streak procs. This requires that you have the downtime in a battleground to stand still and cast, which sacrifices mobility unless paired with the Ice Flows talent, which competes against Scorch and Presence of Mind. That being said Presence of Mind + Pyroblast mages are finally possible again, but unlikely to be seen in PvP due to the improvements of PvP stats and Hot Streak Procs.
Fire Blast is changed to Inferno Blast when playing fire, Inferno Blast deals AoE damage around your target in a 10 yard radius, does NOT stun and is a guaranteed critical hit for moderate damage. This spell should only be used after a crit, for an on-demand Hot Streak proc. Crits done by non-periodic spells are indicated by the Heating Up buff and proc illustration. (Currently a smaller version of the Hot Streak proc illustration)
Improved Flamestrike has been removed from the game Flamestrike currently deals minor initial damage and deals moderate damage over time to players that stand in it. It also triggers a 12 second cooldown which means that Blizzard and Arcane Explosion are now your 'ZOMG THERE'S A ROGUE ON THE POINT, FIND IT!!!' spells - to avoid being interrupted you are only able to spam Arcane Explosion which is highly ineffective for finding stealth classes, especially if Cloak of Shadows is up. Flamestrike at least leaves something the rogue might stand on after CoS ends.