Edit
I had a thought right after I posted this that may fix some issues with how the class plays. As far as my testing has gone, I do not think that spell power, attack power, spell crit, or attack crit work on the minions whatsoever. This would explain the atrocious scaling I ran into trying to plow through the game. This could change some of my issues with the mod but I believe that a majority of my complaints, if not all, are because of the design and bugs, not proper scaling. I haven't done any work in these mods but I do know modding takes a significant amount of patience, effort, and jerry rigging to get working as you want. Please do not take any of this as an insult to your character as others have from my critique in the past. Thank you.
End edit

There is a consistent theme with necromancers, and that is they play extremely slowly but have absolute safety in most, if not all, situations. Though I admire the attempt, I have several issues with the class.

All of the base classes are built to be able to deal with large hordes of enemies via some means, at the very least auto attacks. For necromancer, you have the Efreet. However, this Efreet isn't just for clearing hordes of enemies, it's for clearing everything in the game. It dishes out an incredible amount of damage for so long that literally anything inside its range WILL be dead. This is clearly the strongest ability in the game, and that's saying something since Wizard exists. Several others have mentioned how incredibly easy it is to actually play necromancer soley with this one skill and ignoring the others.

Though the trail of death passive is interesting, it is virtually useless. Typically, in this passive slot, there is a huge power boost waiting for the player to pickup that enables them to dish out incredible amounts of damage. For necromancer, this is entirely not the case. The trail can deal a lot of damage, but it's so impractical that it's not worth even investing points into.

There are only 2 different minions you can really summon. I don't count the Efreet because he's just a frozen orb with a ridiculous timer. Comparing the two at max level, the skeletons are objectively better than the dogs. They're far tankier, deal more DPS, and are summoned in packs of 5 vs the 1. Now, I assume the "downside" is supposed to be that the skeletons require you to cast them whereas the dogs are instant. Considering the typical, boring theme that necromancer tends to take in games, this instant cast time provides no benefit in the grand scheme of things.

Minion targetting is something that I expected to see be an issue in hammerwatch since there's no support for it. Currently, all the minions will just jump to the next guy after they die. This is great for big enemies with big health pools, but this is really bad for clearing. Again, this lends to the clearing problem with this class. Additionally, the minions simply cannot hit big minions. I'm sure this is a bug, but I don't know how you could fix this. A great example are the spawners and the second boss. All the skeletons with clump up and do nothing but still follow the target if they move (this is in reference to the second boss).

The other bug that I've encountered is minions spawning inside walls, rendering them useless. Several others have mentioned this, but I'm adding this into it as well.

This isn't a bug, but this is something extremely important. The minions you summon do not follow you. Now, I used a trainer to just give myself max level so I could test out all its features. I had more success with an auto attack + efreet build than I did with a spectral hound + skeletons build, each using the same two passives and ignoring trail of decay.

What would you change, guy who wrote a long comment on my mod?
1. The ABSOLUTE MINIMUM I would want changed is a way to have the minions follow you. The reason for this is that, though you would start slow, you would have a linear increase in both clear speed and single target DPS. This would entirely offset the sluggish speed the class has. Something as simple as Paladin clears faster and just as safe as Necromancer.

2. An actual 3rd minion would be a great change as Efreet is clearly too powerful. My suggestion would be a temporary big ♥♥♥ (skeleton commander? he's a spinny boy) or buffing skeleton with a cooldown higher than the duration (and maybe have the duration and CD be the same at max level).

3. Spectral Hounds being useful. They're ranged but don't provide anything outside of just existing. They do magic damage instead of physical damage but, in the grand scheme of things, that doesn't really matter. 5 Skeletons will always deal more dps than 1 dog. My suggestion for this would be having them split shot like the elite archers and have the higher levels increase the dog summons to two. This gives them usefulness for at least something. I'd prefer them to also have that spectral tag the ghosts have on act 3 so their projectiles go through walls and they too can go through walls. This thematically makes sense as they're called Spectral Hounds and makes them way better.

4. Remove Miasma from the player and put it on the Zombies. As previously mentioned, this class has a colossal issue with clearing on many layers and it thematically works on the Zombies. If this proves to be too busted, this passive literally making minions not targetting something follow you would be amazing. Could call it Commander of Darkness or something.