It's a bug, they're fixing it in the upcoming hotfix so you should be able to see ailment damage then :)

I'm currently running a highly effective shock/aether/poison DOT build.

Peep my profile for the character (I think?). But yeah, DOT works very well.

It almost hard requires a unique to be effective though.

CRITICISM:
You asked what you need to look for in mods.
The main thing to note is that each tick of damage can only trigger one ailment. That is, without nodal or unique modifiers, your build is fucked from the start.
So first thing is first, get your t1 and t2 nodes for ailment chance and ailment stacks. Once you've got all those, go to t3 and get your t3 ailment nodes. After that, fill in the smaller nodes.
Skills are whatever.
HOWEVER, without a nodal or unique modifier that prevents you from triggering ailments outside of your desired two ailments (since that appears to be the maximum that one can apply per tick barring multipliers), you should FOCUS ON WHAT TYPES OF DAMAGE YOU'RE DOING!!!

I can't stress this enough. If you want to have an effective ailment build, you need to make sure that you are highly aware of what ailments your skills are applying.

Unless mentioned otherwise by the skill (e.g. 'this skill now applies shocked and weakness), skills will apply ailments ONLY for the top two types of damage dealt. For example, if you've got items that give you +fire damage but you want to apply poison and frost only, then get fucked because either poison or frost is gonna get kicked in favor of fire ailments because your damage types aren't right.

Other than that, look for from 40-45% chance to apply ailment,
high tick rate
flat damage bonus
%damage bonus

I'm currently melting tanky lvl 60 superelites with 197% maximum health because DOT builds are amazeballs.

yeah and the unique chest piece that's supposed to make our ailment damage twice as good [Agony] doesn't even work.... it's supposed to increase ailment damage by up to 100% like 0.3% per wisdom point you have but nope.

I changed my gear around, and I just noticed I was going slow because I reached lvl 62 and was fighting lvl 72 mobs... So yeah, it will take a while to kill a boss 10 lvls higher. Thanks for all the tips, btw. I am wondering if I can run a dagger + catalyst, since I dont know how to generate willpower without the auto attacks and the purple blade skill sucks to me.

I think there are several ways to increase your willpower regeneration.

The first and most obvious is to get a few flat "+n willpower regeneration" mods on your gear and then stack % regeneration mods.
Others are:
2) Some skills such as "Shout" (or warcry or whatever I forget the exact name) generate rage or willpower just on account of being used. Using these in tandem with willpower transfer rate mods can also be effective.
3) There is an "bonus willpower on hit" node in t2 on the purple. There are other mods that contribute to on hit willpower bonuses.
4) Run dual willpower potions and account for HP stability through other means.

I just saw some streamers with lvl 70 characters doing 800k damage on mobs lvl 105 (using melee builds).... I dont think I can hit that hard with the ailments. Or I just fucked up the build in some way. I am lvl 64 and the higher I got was to beat lvl 75 monsters, and taking 1 min or so to kill yellow mobs and 3 minutes on bosses... I'm kinda sad right now as I thought it was going great.

@Bollacha

Yeah, you're definitely doing it wrong. :(

I really recommend visiting the t3 purple passive tree mod which doubles damage that follows the Stasis ailment.

Another thing: I'm beginning to think that poison, burn, and aether are the ultimate damage dealing ailments, since there is just so much added support for them.

Lightning and Ice seem to have very little item/passive support.

Burn has the t3 red passive mod.

Poison has the drain skill which is stupid good, as well as the t3 passive mods plural which boost it.

And aether is self explanatory. That t3 occult passive mod is ridiculous.

Would you happen to have a build link? Kinda curious on how to build a decent ailment stacker. Weapons of choice?

@Linksys

Aw, crap... I'm using Anomaly, tear, plagueburst and annihilation as damage skills.
I'm focusing on poison damage for the most part. It does 450~5100 damage (tooltip info).
Plagueburst does shock and poison damage
Anomaly does stasis and poison damage
Tear does Freeze and Poison damage
Annihilation does shock and poison damage
Well, ailment wise, I mean.
Idk how I can upgrade it, I am heading to the Stasis node that gives 100% damage after 1,5s. I'm at 54k hp and 3,2k force shield, with around 71% damage resist
I am using a staff with +55% poison ailment damage with gems giving +21% poison ailment damage and one providing 17~17 toxic damage to spells.
https://imgur.com/j7vv5fB
https://imgur.com/a/4xNOA9A

Idk what to do. I can, with ease, tank the higher mobs, like 75, just need to dodge once in a while and the hp regen does its trick. But, the kill takes ages. I got a boss with regen + summoning adds that healed, it took around 10 min to kill it.... I dont know what to do, invested so much time in this character...

I tried something different, I aimed for a DoT-Build focused on holy and shadow dmg to weaken or curse the shit out of them (dependent on what attacks I use) and finish them with schock and burn.

That build is possible, because my main skill is "infinite blades" which I skilled that they trigger shadow dmg and allow me to use warrior skills.

With this build my warrior-skills apply holy and burn and my spells apply shadow and schock and I melt everything with it, especially with the abyssal herald build it is devastating to enemies and bosses alike.