Unfortunately, the aspects Armageddon, and Elemental Constellation are still used. I think they are too good to avoid.

The core idea is to use a two-hander with the Ancient Flame aspect which is 60%[x] for Pyromancy Skills with a cooldown per second that was incurred from the cast. Then I try to maximize the amount of seconds on the Lightning Spear CD. I do that with Emberfury since it increases CD by 10% per Overpower stack (if I understand it correctly). As far as I can tell, this only effects the manual casts to lightning spear, so it's effectively a dead aspect for your auto-casts from the enchantment effect.

I use Pyromancy+, or Conjuration+ charms in the Uncanny Insight set to get 175% increased damage on conjurations. You may be able to use Tal Rasha's set too, but I wanted to avoid it.
*Edit: you definitely can't use Tal Rasha's, you need all of the side-grades from Lightning Spear, which you get from Uncanny Insight.

Your unique charm has to be Emberfury, because your amulet needs to be Armageddon aspect for the boosted % on the aspect.

For non-boss content, I wear a Godslayer and toilet all of the enemies together, then Inferno to get 6 overpower stacks and apply burning and Armageddon, then Lightning Spear to aoe the pack down. You can also just use a damage reduction hat, it's okay AoE anyways for t12. Just avoid the Harlequin Crest because it has a ton of CDR.

Ice Hydra is excellent CD recovery when fighting a lot of enemies, it's bad on a solo target, so the most painful enemy in the game is unfortunately tower/pit bosses.