Arcane has now surpassed fire as the spec of choice for raiding mages. The GuildOx Spec Rank
now shows arcane has grown to 45% of the top 5% of raiding mages, where Fire has dropped to 39%. Less than two months ago, Fire made up close to 90% of raiding mage specs with Arcane at around 3%.
The reason for the decline in fire? Late November saw a tuning adjustment to Fire mage dps in the form of a nerf:
The periodic damage from Combustion has been reduced by 50%.
The critical strike chance multiplier from Critical Mass has been reduced to 1.25 (was 1.5).