I don't know if this is still what's planned, but this is what it used to say on the skill:
Casting Energy Twister grants you a Wind Charge. You can store up to 3 Wind Charges at a time. Casting a Signature spell releases all Wind Charges as a giant Energy Twister that deals 75% weapon damage as Arcane per Wind Charge.
The following skills are Signature spells:
Magic Missile
Shock Pulse
Spectral Blade
Electrocute
Energy twister whit the rune "Storm Chaser" ?
http://eu.battle.net/d3/en/calculator/wizard#...V!!...c
must be some wrongs here... maybe the runes makes it a signature spell, but still, the tooltip is then wrong... :I
Source: http://www.diablowiki.net/Energy_Twister