The issue I was having with the Frenzy barb not attacking appears to be resolved. It seems to be failing to pop WotB along with Earthquake on most of the elite packs it comes across when both are off cooldown, however. It will use one or the other, but rarely both (always at full fury). No noticeable micro-stuttering during combat.
Yep my barb with Earthquake does not use it at all. Changed skill to rend and will post back with results, but i quite liked using Earthquake and WotB against elites as it would usually rape them quite fast.