Rudi89, interesting, I wasn't aware of a nochanneling modifier - I'll have to check that out.

Last night I respec'd my mage back to heavy Arcane, with 3 points in Fire for the crit, and the rest in Frost heading toward Icy Veins (but can't reach it yet). Doing the following rotation her dps was back up nicely:

/castsequence [target=focustarget,harm] Arcane Blast,Arcane Blast,Arcane Barrage

With the major Glyph that increases Mana Shield from the normal 30% regen rate to 50% regen rate, and the mana totem, and Judgement of Wisdom being used - she never ran out of mana, even in boss fights.

So my belief in Arcane is back, and I'm much happier with the higher damage output again. Thanks for the ideas guys!