Diablo III- Skills Article CXXXIII: The Wizard, Secondary Skills- Arcane Torrent

Arcane Torrent (20 Arcane Power per Second): You send a barrage of Magic Missiles arcing towards the target location through the air that deal an average of 175% weapon damage as Arcane damage to all human-sized enemies in the area.

Arcane Torrent is an interesting skill that, sadly, is not as clean as its tooltip implies.  Since the projectiles are semi-inaccurate and each one only deals a small portion of the damage, while the effect claims to be targeted against one enemy it really has a small area of effect.  Each projectile lands in a random point in that area, roughly two to three yards across.  This makes Arcane Torrent much less powerful against a single target than against a small cluster of enemies.  It’s still better at damage-to-Arcane-Power value than Arcane Orb, but with a much smaller area and random landing points, it’s actually less effective for damage over time.  The trick is that you can hold the skill, continually barraging and drawing the target area across multiple enemies.  This makes it a bit better than Ray of Frost in some situations, such as when your target is behind another enemy that you don’t particularly care if you damage or not.  Still, overall, this is probably the least overall effective of the Wizard’s Secondary skills, though it isn’t outright bad by any means and is quite fun to use.

Disruption (20 Arcane Power per Second): You send a barrage of Magic Missiles arcing towards the target location through the air that deal an average of 175% weapon damage as Arcane damage to all human-sized enemies in the area.  Enemies hit by any of the projectiles are Disrupted for 6 seconds, taking 15% extra damage from all sources that deal Arcane damage while the effect lasts.

Best used alongside other sources of Arcane damage, Disruption is a good source of weakening if you want to use your Secondary skill to support your Primary skill and hotbar skills.  The effect also boosts the damage from the skill itself, so it adds a modest benefit that can take Disruption up to a higher damage capability than an unruned Arcane Orb.

Death Blossom (20 Arcane Power per Second): You send a barrage of Magic Missiles arcing through the air in random directions which land up to 20 yards away and deal 670% weapon damage as Arcane damage to any enemy hit..

If you want to reserve your Secondary skill for emergency situations where the screen is crowded with enemies, Death Blossom is probably your best option.  While you can’t control where the missiles land and they don’t launch all that rapidly, the damage they deal is very impressive, so if you’re in a crowded area and you have someone on hand who’s protecting you from enemy attacks, this skill can be fairly strong.  Not recommendable if you’re playing solo, even with a Templar helping you.

Arcane Mines (20 Arcane Power per Second): Launch four to six projectiles every second at the target location that sink into the ground as mines.  These mines arm after 2 seconds and deal an average of 150% weapon damage as Arcane damage when they explode to all enemies within a 2-3 yard range and Slowing the movement any enemies hit by 30% for 3 seconds.

While an interesting effect, if you want to be laying down mines and explosives, you should probably be playing a traps-oriented Demon Hunter.  That said, this can be an okay utility spell, but you probably won’t want to use it to empty out your whole Arcane pool- you might be able to start a fight with it and catch some enemies in the damage, but the damage is lower than Arcane Torrent and the slow effect is very small, though it has a nice duration.  Might be worthwhile to try and kite if you combine it with another slowing effect.

Power Stone (20 Arcane Power per Second): You send a barrage of Magic Missiles arcing towards the target location through the air that deal an average of 175% weapon damage as Arcane damage to all human-sized enemies in the area.  Every time a missile hits, it has a chance to leave behind a Power Stone that can be picked up and restores a little Arcane Power.

Power Stone is a very unusual sort of rune.  There are very few skills like Arcane Torrent- a secondary skill meant as a continual resource dump- that give you a way to regain that resource.  The problem with this is that once you stop spending your Arcane Power, you regain it rather quickly- and you’re not likely to have time to gather the Power Stones until the fight ends anyways.  This makes them less useful than they could be, as does the fact that Arcane Torrent is a skill that you hold still and use over a protracted time, so it isn’t as though you can gather them in between bursts and still keep up sustained damage.  So, while Power Stone is an interesting permutation, it isn’t, strictly speaking, strong.

Cascade (20 Arcane Power per Second): You send a barrage of Magic Missiles arcing towards the target location through the air that deal an average of 175% weapon damage as Arcane damage to all human-sized enemies in the area.  Whenever this damage kills an enemy, that enemy’s corpse launches a new missile at a nearby enemy that deals 175% weapon damage as Arcane damage, and can trigger this effect.

Cascade is probably the ultimate form of Arcane Torrent- the fact that it can follow its name and cascade through multiple enemies makes it vastly more powerful than any other rune for the skill with the possible exception of Death Blossom.  This is, however, only in terms of raw power, and only comes into effect if you hit what you’re aiming at- a little bad luck can easily leave the effect not firing.  That doesn’t make the skill rune bad- just not as good as it could be.  Certainly worth using if you’re not inclined to use Disintegrate instead in the late game.