Vote for Harvester deletion from the game.
I unsubbed twice due to frustration while fighting them. Always have to use every ♥♥♥♥ I can imagine to fight them including my my fancy DK banner.
The stun sucks, the heal sucks and their dmg sucks. They are plain and ridicilous OP.

And please don't come with some ideas like "use Desto or Bow" when none of these weapons are leveld over 10.

You don't necessarily need AoE for the orbs. It's possible with single target too. My templar tank is doing fine against them.
Tips:
- start with ultimate and refill your ult bar when killing the orbs
- at Dark Anchors you can dodge them: kill everything else and clear the pinions. Those get unlocked even if just one enemy is missing.
- try grouping for Dark Anchors. Soloing them isn't supposed to be easy.

Some key things to remember when fighting Harvesters:
1. Use the break out feature as soon as she grabs you and summons her orbs.
Don't just sit there waiting for her to release you, your gonna lose precious
time taking out those orbs.
2. Go for the orbs asap. This is easier to do with ranged weapons or AoE.
3. Her wave attack can be interrupted. Try to interrupt it often, not only will you
avoid some heavy damage and knock back but it will stun her for a few
seconds.

Major thing to remember with Storm Atronachs:
Don't bother trying to kite, their snare is pretty much inescapable. Trying to get distance is only going to give them free hits. As crazy as it sounds it's better to engage in melee with skills that increase armor/damage reduction/dodge chance.

Melee's also a better option because you can actually interrupt their power attack. You have a really limited window of opportunity that you can't make with ranged attack because of the time it takes for the skill to go off and connect. However bash can get it easy. Once you get the rhythm of interrupting the power attack, Storm Atronachs are a simple tank and spank job.

OK, I hate them as well. Especially in a tomb i Bangkorai, in a quest that is essential to the covenant questline.

There is no challange, they are just f*cking impossible to kill. I tried both ranged and melee, several different tactics. I can´t kill them on my own, which is a severe design flaw. I´m about the same level as them so the challenge is really unfair.

Holy Necromancy!

That is an old post to resurrect @Kithain

What class are you? They all have a class AoE and a class ultimate AoE that can be used. You may have to slot a different ability for the fight but they are definitely soloable at your level even in close quarters like that.