The only Part where Tanks have it a lot easier is the second last boss. The stairs with all the mini spiders is horrible for everyone else who cant deff CD thru it and then slowly AoE the hell out of those tiny spiders. The rest is just a question of tactic and Talent choice.
I Do them as Boomy and never ever do I go there without Mighty Bash. Most bosses (if not all) aren't Stun immune making them reaaally easy. If you set out a good route and collect withered in the right manner you should hit Dro with around 35 Withered. I lost aroudn 4 before the better upgrades. After you get dro yo can easily get to 40 withered and take on Elfbaine and loot the +25% dps chest. If you have really big problems then maybe start slowly and take the earlie chests and get further each week.