Leveling Minion Witch without Flame Wall / Raging Spirits

The Flame Wall / Raging Spirit combo is easy and strong and very effective, I just don't like it. When I play a Necromancer, I want the skellies and zombies and dark magic, bone, blood etc.

With that in mind, I wanted a more involved playstyle and I think I'm doing it, I'm just not very proficient with PoE as a game. So any ideas welcome.

To mitigate the damage loss from not using Flame Wall / Raging Spirits, we need as many minions as possible. For this reason, all the spirit goes to our minions. That means, no spirit persistant buff and also making a straight line for the Lord of Horrors passive. If you have access to a Lv15-20 armor piece with +Spirit, even better.

Another way to increase our overall damage is by attacking ourselves. The Contagion / Essence Drain combo takes us very far without any Chaos damage investment in the passive tree. Contagion can have Magnified Effect for spread and Essence Drain can have Blind for a bit of protection, I also slot Pierce to shoot multiple enemies at once. Bone Cage slotted with Pin and Spell Cascade is an awesome crowd control skill to immobilize enemies. During Act 1 and the Majority of Act 2 we're not taking any minion defensive passives, so immobilized enemies who don't attack are extra defence for the minions, and us.

Now at gem Lv5 we get access to zombies which I love and I absolutely wanted to use. They're quite slow so for now, slot them with Minion Instability and Brutality for some more damage in groups.

At gem lv7 we get access to Vulnerability which is a great curse but also, Profane Ritual. Now Profane Ritual doesn't see much use in Witch builds but here, we take advantage of its effect to generate Power Charges. We use our Power Charges to summon Zombies which normally require a corpse to summon. We can have up to 3 charges to summon 3 zombies but that's quite a slow process, so we slot Unleash and Profusion in Profane Ritual and we change Minion Instability on the Zombies to Perpetual Charge.

- Unleash: Any spells that we cast have their effects reoccured automatically. Using Profane Ritual now gets us more than 1 charge, most often it's 3 of them immediately.
- Profusion: Supported spells have a 50% chance to generate an additional charge. This means that we're now almost always getting 3.
- Perpetual Charge: 35% to not consume a charge. That 35% is quite generous actually, I've been able to summon 10 zombies off of 3 charges, all of them obviously empowered.

All this means that while clearing a map, you start each fight with empowered zombies. The charges have a 20 second cooldown, that + the duration of the zombies means you pretty much never run out.

I am currently in Act 2, this is my 5th playthrough so I know how it goes, but the main issue I haven't been able to solve is boss damage. The build is great for add clear, but bosses don't have corpses, so half the build is not being used. Where Flame Wall / Raging Spirits is a self-sustained combo, here I only rely on my Warriors and Arsonists to do damage. I'm looking to replace the Arsonists with Reavers as soon as I can.