You really need to gear up to the level you're fighting, and that is definitely easier with friends. Don't overlook crafting as an option for gear upgrades, although sometimes you might have to roll the same gear multiple times to get the right stats.
Poison darts are lame, and I seem incapable of actually using my weapons. I'm not even sure if my weapon's stats do anything.
Fucking hated this, still fucking hate it, on first playing the game. All ability damage is derived from your weapon damage, so, it does something. It's just counter intuitive. Blizzard cared more about having a look and a feel to attacks that was at odds with putting the weapons in the animation, or trying to figure out how to make each one work with weapons. So they just tossed the idea of actually USING your weapon in whatever you do.
I think the main cause of this is the permanent +50% experience I for some reason have.
It's bonus that's been running for two weeks, the lead up to Reaper of Souls releasing. Intended to entice people who'd quit playing to come back and get geared/leveled fast. It's an incentive for everyone really. I've watched my 160 level paragon put on 20 levels since it's been going.
Here's my experiences with WD so far:
You have 4 rough builds.
-Close up nuker/DoT
-Range nuker/DoT
-Pets
-Support
In the beginning of playing WD, I was a range Nuker/Dot. I'd use Corpse Spiders with the mana rune for my Primary, Acid Cloud for my consumer/aoe damage, Grasp of the Dead to snare guys for Acid Cloud, Spirit Walk for escape and mana regen, and a free ability to mess around with, usually Soul Harvest for the Int Buff.
And what I found was that early game, you're outclassed by melee, and late game, everyone is outclassed by Wizards.
So I got rid of Corpse Spiders as a primary. It is very popular to create builds that forgo a "builder" attack in favor of using a secondary attack (resource consumer) as your primary. You're trying to create that feedback loop, through passive skills, skill runes and gear, so your powers fund themselves, or so you have a reliable resource regen method you can call on that isn't a builder attack. While Corpse Spiders is nice, late game you'd end up throwing spiders for 2x as long as you'd be DPSing.
With WD, I went Spirit Barrage for a primary, Acid Cloud for a secondary. Using the Passive Skill for Spirit Spells, Spirit Barrage will basically refunds itself on cast, so I can spam it til the cows come home for quick, single target damage. Acid Cloud is still good for quick instant damage and a little AoE. I opted to give up the slow and dot of Grasp of the Dead for Charging Zombie with the Zombie Bears rune. Makes for short range aoe that does a crap ton of damage when sustained. Still keep Spirit Walk for trouble. Instead of trying to compete with Wizards for DPS, I used my last two slots for Witch Doctor support spells, Big Bad Voodoo and the Fetish. The Fetish will polymorph guys (great for making elites and champions less of a problem) and the pig takes 10% extra damage. Meanwhile, Big Bad Voodoo will give out 20% damage and attack speed while people are inside it. So between those two, I can buff group damage by 30% against a single target, or 20% against all targets for 30 seconds.
So I've kinda mixed 3 of the 4 builds into mine. I could probably lose the Zombie Bears but they're just fun. WDs can play either near or far but they don't get the benefit of a lot of personal defense options like Wizards. They get a lot of survivability out of their gear which, with their short range options, would imply they're tanky. But they're still casters and can't face tank stuff for long without a shitload of life on hit. The damage on their spells, while nice, is often too slow or too specialized to kill in groups when up against Wizards. (And trust me, I've played with a lot of Wizards at this point.)
As for pets, I know it works but it takes the right runes on the right skills, with the right gear, and even then it's hard for them to put out the quick DPS players can. I got a legendary the other day that just added straight damage to all my minions. If you don't have Gargantuan yet, you might try him, I think he gets pretty beast and can tank for you.
I like playing WD when I'm feeling lazy. Wizard does more damage but they're somewhat frailer. And if you're in a diverse group, those damage buffs can really accelerate the murder.
The game is incredibly easy
Get to Hell and Inferno and it will be annoying its difficulty (assuming they didn't fix it)
They really did. The differences between Torment 1-7 are noticable, and # of players greatly affects mob HP count. So it's easy to tune for the "sweet spot." I can solo Torment 3 on my Wizard currently, with 120k damage. But add another player and stuff takes noticably longer to kill. My bench mark is white mob damage. If you get surrounded by little fallen demons and they strip your HP from you in seconds, it's a safe bet you're on the harder side of difficulty. If you can face tank a small pack of whites without using potions, you're probably in the right place. If whites die in 1 or 2 hits, you can probably bump it up.
Later difficulties, it's all about the quality of your equipment. The best build will only get you so far in this game. If you can't hack it at the difficulty you're trying, you have to bump it down and keep farming for the gear with not only the right stats, but the best rolls of those stats.
The real challenge of the higher difficulties are the champions and elites. They don't hit for as much as they used to, but the combination of 6 abilities firing off at once can still flat out kill you. If elites are almost one shotting you with their regular swing, your gear isn't where it should be. Beyond that, it's about how much damage your gear affords you (modified by skills.) Elite abilities are designed to kill you quickly, and they have to be avoided constantly, and somewhere in there you need to do damage. So it's about attrition. The longer you spend trying to kill mobs, the better the chance you'll eventually be surrounded by enemies, frozen in place, feared into arcane beams and so forth. So high DPS, combined with life on hit and timely use of heal pots and constantly being on the move avoiding damage, is what gets you through fights.
I try to keep my builds to 2 to 3 damage abilities, and the rest defensive in nature. Always, always have your mobility/oh shit ability equipped, because those elite abilities will end you without them.