as I remember I did around the same amount of damage with 2h stormblast as with 2 1h but after all 2 1h should do little more damage due to 7% extra spell power, from flametonue since you cant have both wf and ft on one weapon you lose one imbue, but the biggest problem is the weapon swing timer reset when you switch weapons, you'd have to switch to the 2h about 3 secs before you burst because the auto hit does significant damage

anyway I stay with 2 1h