What are your stats? I just got to act 3 inferno with my WD, and although I didn't try it too long, it seemed like it was going to be a lot harder than act 2.
~40k DPS
~30k HP
~300 resists
+25% run speed.
~2.3 attack speed
I want to add some more attack speed but I can't find attack speed gloves that have same or better int/vit as my current gloves. Even if I did they'd probably cost > 5mil.
I use wall, grasp, poison darts, horrify, hex, and spirit walk.
Passives are Pierce the veil, Blood Ritual and Spirit Vessel.
The start of act 3 is much harder than much of the later parts, IMHO. Giant packs of fallen with the mages reviving the imps makes it hard to clear as a WD. You basically have use spirit walk to get in close enough to kill the mage(s) and then hope you get back out before the imps destroy you.
The parts inside the keep are much easier because you've got plenty of chokepoints. Once you can get Tyrael to fight for you it gets even easier, lol.
What I've been doing is this:
Start at siegebreaker checkpoint.
Check bridge room for chest. If not chest restart game.
If there is chest, clear area, getting 1 stack from elite pack if they're not too nasty. Leave the chest for now.
Go back and do levels 1, 2, and 3 of the keep, building your stack, looking for more resplendent chests. Very few packs I can't kill with a little help from Tyrael.
Once I have 5 NV stacks I go back to town, get my magic find suit.
Kill siegebreaker, swapping to mf gear right before end of fight.
Loot every resplendent chest I found (I've found one on at least 2 of the keep levels to go along with the one right before siegebreaker).
Knowing the proposed itemization changes for 1.03 I've kind of lost interest in farm runs, though, so I'll probably just goof around to the end of the month.