I needed an upgrade to armor/weps about the time I hit Act3 and then just blazed through NM with no problems on huge packs of mobs and 'tank&spank' with the mobs.
I am now in Hell with the following stats:
52% damage reduction
Most resists at +15% reduction , a couple at +20%
I've also changed my skills to the following:
I need to turn on elective to give myself the heal as well but I'm so confortable with this build..... (Except against elite packs that link together)