Theorycrafted this build around the cheap Consuming dark daggers, ideal for league start.

https://pastebin.com/1VAQjRn5

Capped spell suppression, decent critical strike chance, 4k life and 3k Energy shield. No armour whatsover (need flasks to fix this).

Cast speed rolls might be a bit generous.

Onslaught boots to further maximize your cast speed for really smooth gameplay. Higher Evasion rating would be desirable.

Reminds me of chaos incinerate occultist in 3.3 which felt pretty great, maybe I try this as a second character.

Edit: if you swap in Immolate and tick ignite, the DPS actually goes up to 3.1Mil.