MAX CDR on every piece recommended except neck where you want Fire%, double Crit + socket.
EB Skilldmg on Shoulders and Chest Armor.
Other than that pretty standard rolls.
Always use Arcane Torrent to:
-Buff your Dmg and Toughness (via Taeguk, Mantle of Channeling and the skill itself)
-Autocast EB and BH based on your CDR (don't need to cast BH yourself)
-Ignite Mobs (EB, Torrent, Magic Weapon)
-proc Arcane Power on Crit.
Teleport when necessary. That's it.
Keep in mind it's FB. So find elites and then fight.
For Groups I would recommend swapping Halo of Arlyse for the Obsidian Ring.
With some optimizations (Arcane Power issues) you can In-Geom-like spam EB. But Groups don't want you with non-Archon builds so don't try it ;D
Skilldmg (Woh, Shoulders, Chest Armor), Blackhole, Taeguk and Magic Weapon are all in the same buff category so they're all additive
That's why changing Taeguk is a viable alternative (e.g. for Gogok)
I usually run with Blackhole: Event Horizon but Spellsteal obviously is a tiny bit more dmg. Decent in high density.
Casually cleared 80 with this (non-ancient Woh, only 79% Skilldmg overall on gear).
I'm pretty sure I can get into the high 80s with some optimizations. I feel like it's one of the strongest non-Archon builds you can run atm.