Gear and skill count far more than racial characteristics. I've played a mage for most races and never felt that one race or another gave me an edge in killing a mob or a player faster.
At level 90, Arcane Torrent returns 6k mana every 2 minutes. It's quite useful as a silence/interrupt for melee classes, but given its relatively short range and meager mana return at max level is among the least impressive racials for a mage.
True but I look fabulous!