You do have to realize however that if they can crit, that even if I have half of the crit fire has, my crits are going to do even way more than fires lol. If it's a 35k over 4 seconds for fire, if it crits its 70k. With arcane my non-crits are literally almost 70k. THEN if it crits... Plus if you have wushoolays or twoshoolays proc'd, or two int procs procc'd...Not only is the dmg going to be like 150k for an arcane mage over 4 seconds, but if it crits as well.
Now the damage over 4 seconds I am not sure if it is 1 tick/second or how it's done. So in reality fire would get 2 tick crits probably to my 1.
If that is the case quick math at 40k sp and 90 mastery (on ptr with raid buffs and the i553 gear lol)
Fire 4 10k ticks, if you have 50% crit fully buffed then your gonna have 60k damage.
Arcane 4 19k ticks, about 25% crit fully buffed it's going to be 95k damage.
Lets say wushoolays and twoshoolays proc and you have about 35k more int so lets say 75k sp. Crit will go up a chunk too, but for the sake of simple napkin math we'll leave it at 50% and 25%.
Fire 4 ticks of 18.75k with 50% crit you'll have 112.5k damage total
Arcane 4 ticks of 35.63k with 25% crit you'll have 178k damage total
I want to say the difference between test 1 and test 2, fire had a 35k difference in test 1, and test 2 a 65.7k difference. So with fire it does scale better, obviously though because that's fire. It scales better, always, even with legendary cloak procs. HOWEVER we'll never get to a point that fire exceeds arcane's cloak damage this tier because we're not going to hit hundreds and thousands of intellect which is what fire would need to pass arcane. Arcane scales consistently, fire exponentially. However the cloak proc is still better on arcane since it just does more damage flat out.
However fire does proc more because of more damage...So I can see where fire catches up.
So it evens out.