I've done this dungeon on +3 difficulty.

My way to beat the spider boss is to swap my focus to one of the two toons with web/link and to use that toons mobility ability to run away ASAP while watching for the blink strike. My paladin has a stupid easy time of breaking the web link because it actually has a good mobility ability. My dks are much slower but I pop wraith walk and try to break it as fast as I can.

I make sure my toons are not swarming with IWT so that they can strafe or more forward or backwards to dodge the blink strike and clouds of crap on the ground. I'm always watching for this while I'm running away to break the link. Sometimes, I'll also move my slaves the opposite direction as the one who I'm manually moving away, so I break the chains faster since 2 people moving opposite directions will break the chains faster than one.

The key I have found (besides breaking the chains ASAP) is to also kill those spider adds ASAP. If you don't they will root/stun your toons and possibly trap you in a blink strike or cloud of bad.

I typically can do this fight within 1-2 attempts. What sucks is when she chooses the same toons over and over again for link and they are out of mobility CDs (not that DKs have much of that in the 1st place!).