Main method of attack for mobs (mobs being main groups). Cast arcane orb (orbs surround you). Teleport into the middle of the pack of monsters (this will cast 80% dmg wave of force on top of detonating all of the arcane orbs x4). Next you can cast a few Siphoning Strikes to gain some ap if you aren't maxed and cast Frost Nova, next cast a few more Siphonings (with any luck you'll trigger the 50% chance to cast another frost nova on killed enemies cascading the freeze effect for the duration of the mob). If the mob unfreezes and continues toward you, cast wave of force to finish off stragglers.
Of course when Archon is cooled you can use it after teleporting into the mob to wipe them all out and go on a rampage.
Passive idea is to reduce cooldowns as much as possible. Possibly swap Blur with Arcane Dynamo to boost some dmg.