This build has been tested on version 2.6.0 in original format on PS4 and PC, in 2.6.1 PTR, and in Season 12 on PC and PS4.
This set build has been rather rejuvenated with the 2.6.1 patch to put it on even grounds with Tal Rasha's Elements and Firebird's Finery as a viable alternative set to Vyr's Amazing Arcana in terms of raw power and damage potential. The boost to the Frozen Orb rune for Arcane Orb has helped it even more so, and this build stands on the strengths of the set and associated skills without spreading the offensive and defensive ability between too many of said skills, instead streamlining a more direct offensive and defensive set up that is viable at any damage range.
The Delsere's 2 piece bonus allows for three of the four Signature Skills (Magic Missile, Shock Pulse and Spectral Blade) as well as Wave of Force, Explosive Blast, Arcane Orb, and Energy Twister to decrease the cooldown time of Slow Time by 3 seconds per cast, making the 15 second cooldown of the skill erasable with just 5 quick casts. The 4 piece bonus grants 60% damage reduction for the Wizard as long as least one Slow Time bubble is active on the field, with a 30% damage reduction to any allies within the bubble's radius, and the 6 piece bonus allows all enemies affected by Slow Time and for 5 seconds after exiting the bubble's radius to take 3800% more damage from the previously noted Signature Spells and Arcane spenders.
The streamlined approach to the build utilizes only three of the required skills, Magic Missile, Energy Twister, and of course Arcane Orb. Arcane Orb with Frozen Orb allows the firing of ravaging projectiles dealing 950% Cold damage to enemies in a 15 yard radius around the orb's path that hit enemies multiple times, then detonates in another 950% damage explosion at 40 yards, the highest damage rune for the skill and granting a huge damage radius all around the Wizard. Energy Twister is a high Arcane damage spell at any range, and with the Raging Storm rune can double their damage, radius and duration by any two smaller twisters merging, essentially doubling their overall value especially when rapidly cast. Magic Missile by itself is a quick but weak Arcane damage dealer, but with the Charged Blast rune boosting damage to 325% and the effects of Mirrorball tripling the projectile count, it becomes a rapid heavy damage attack on par with Frozen Orb, and paired with the Shame of Delsere belt, attacks 50% faster and grants between 9-12 Arcane Power to fuel the other skills upon hit. All three hit the parameters for wide short to long range damage, widespread damage at range, and single target heavy damage at variable range respectively.
All three being cast chew through the cooldown of Slow Time, making it well able to be cast to the degree of being active almost non-stop. The sphere itself lasts 15 seconds, so quick enough casting should allow the skill to be re-cast before the previous bubble's duration even ends. The Time Shell rune helps speed this up even more by dropping the cooldown to 12 seconds, making any 4 casts of the aforementioned skills erasing the cooldown entirely. Use of the Crown of Primus in the Cube adds all the other runes to the skill as well, making it all the more valuable to keep casting as often as possible. To facilitate this even further is the Mirror Image skill, creating 2 duplicates of the Wizard that Taunt enemies for 1 second and have 50% of the Wizard's health pool each, while casting all the same skills as the Wizard has equipped at 10% of their damage, allowing multiple free casts of Slow Time simultaneously that can overlap over a single larger area or over multiple smaller areas at once to handle more enemies. Also with use of Bane of the Trapped, any attacks dealt by the Mirror Image copies are boosted from 10% to 25% or more of the skills' damage ranges, a nice little bonus on top of their casting Slow Time.
The rune choice for Mirror Image is between the Extension of Will rune, extending the Mirror Image's duration from 7 seconds to 10 seconds and granting each copy 100% health instead of 50%, and the Duplicates rune, which summons 4 copies instead of just 2, all with the same base time duration and health pool. The former works better for getting in more casts of spells, especially Slow Time, for the duration of the skill, whereas the latter works for tossing out a higher number of spells in a shorter window. The copies all vanish at the end of their duration regardless of remaining health either way, so it's a matter of player preference on this one.
The final skill is Storm Armor, an offensive based Armor spell that lasts for 10 minutes per use that shocks enemies at any range for 175% every few seconds, but the damage dealing of the skill itself isn't the focus for this build. With the Reactive Armor rune, Storm Armor also shocks any enemy that hits with a melee or ranged attack on the Wizard as well as the normal shocks fired off every few seconds, though the damage is boosted slightly to 189%. This increased usage synchronizes with the Halo of Karini in the Cube, granting up to 80% damage reduction for 5 seconds every time an enemy is shocked by Storm Armor past a range of 15 yards from the Wizard. This makes for a very easily maintained and managed damage reduction bonus to aid survivability for the build, especially for combat in Rifts and Greater Rifts where there will likely always be enemies grouped outside the 15 yard range to be shocked on attack or on the normal timed shocking casts by the skill. The damage the skill deals when the Convection of Elements is on the Lightning rotation is also a not too shabby 389% per hit, which isn't a bad bonus on top of the damage reduction.
The passives support the streamlining of the build's attack skills, mainly with the Illusionist passive, which resets the cooldowns of Slow Time and Mirror Image when taking 15% or more damage within 1 second as well as granting a 30% movement speed bonus upon casting said skills, making them usable even more often when taking damage as well as with casting the associated skills. Arcane Dynamo supplements said casting, making for every 5 casts of Magic Missile to grant Arcane Orb or Energy Twister an additional 60% damage, and Dominance and Unstable Anomaly grant health shielding for better defense upon killing enemies and preventing fatal damage respectively, synchronizing with the shielding from Molten Wildebeest's Gizzard.
The build does have some equipment variations. Unstable Scepter grants Arcane Orb much more damage and a secondary explosion upon final impact which of course works with the greater damage boosting by Triumvirate in the Cube or equipped, and fits the balance of the build outright. However the build can take a heavier focus on the Cold damage, swapping Unstable Scepter for Rimeheart to grant a 20% chance to inflict 10,000% weapon damage to any Frozen enemy. The Freezing could be achieved through Freeze on Hit on the weapon or other equipment, or through swapping the Charged Blast rune for Magic Missile to Glacial Spike, allowing it to Freeze enemies within 4.5 yards on impact for 1 second every 5 seconds for 175% damage. Multiple Glacial Spikes could be cast with Mirrorball, or swapping Mirrorball for Winter Flurry which would add a 15-20% chance to detonate Frost Novas to Freeze surrounding enemies upon the death of any enemy killed by Cold damage from Glacial Spike, Frozen Orb, or if there's a Cold damage roll on Rimeheart itself to affect all skills.
Conversely, there's the option for the swapping or addition of the Paralysis passive via Hellfire Amulet, allowing Lightning skills a 15% chance to Stun enemies for 1.5 seconds. Doing so would make the Manald Heal ring a viable Ring choice, hitting any enemy inflicted with Paralysis with 13,000-14,000% weapon damage as Lightning on top of the base Lightning damage from Storm Armor and making it viable for offensive as well as defense, getting much more bang for your buck.
To make the build a full 4 element build and get the most out of Convection of Elements would require swapping the Charged Blast rune for Magic Missile for the Conflagrate rune to make it Fire damage and add a burning DoT effect on hit to enemies, able to stack huge amounts of damage on when tripled by Mirrorball. This would allow the use of the Elemental Exposure passive by swapping/adding with a Hellfire Amulet, and would technically open the build to use of the Primordial Soul Source as well for equipment, though likely at the expense of the use of Mirrorball. Lastly, with any such variation on the build another weapon choice would be the Wizardspike dagger, allowing any attack a 20-25% chance to cast a free Frozen Orb as an overall boost to base DPS.
While the 30% damage reduction for allies within the Slow Time bubbles does technically make for use in group play, the build unto itself is designed more as a solo build, lacking any other support/healing options.