3.4 Blade Vortex Summoner (WIP, Suggestions welcome)

Looking at the new minion passives and herald of purity I wanted to combine two of my favorite builds, Summoner and Blade Vortex. Given all the increased skill duration from going Necro, plus having Minion damage also affect your damage I feel like it should theoretically work, especially as a budget/starter build. I'm not entirely certain what links or items to use yet as this is my first attempt at making a build from scratch.

PoB: https://pastebin.com/AUaWcMVn (items are just filler items for now)

Main Gem links I have atm are
Vaal Blade Vortex - Conc Effect - Added Chaos Damage - Controlled Destruction - Efficacy - Added Fire Damage
Herald of Purity - Summon Phantasm on Kill - Minion Damage - Minion Splash (Depending on how well the minions from purity work might want to swap in melee damage supports instead)
Vaal Haste - Spirit Offering - Increased Duration

Possible Uniques I'm thinking to use are Coming Calamity and Essence Worm which would allow for the use of an extra Herald plus + aura. Would like to see how well Herald of Agony works into the build along with Severed in Sleep/United in Dreams but I think it really depends on how powerful the minion is since I don't really grab anything to scale poison.