I don't know about the other barbarians out there, but I facerolled through normal, nightmare and currently halfway act 2 of hell with zero issues or hiccups.
Everything still dies in the blink of an eye, and I haven't found a single elite I couldn't take on yet, even if some of them take a second attempt. (fucking arcane enchanted bastards)
I think the people having difficulties with barbs in nightmare/hell need to take a long hard look at their build and gear, because frankly, I feel somewhat overpowered and i'm progressing through hell quicker than I did on nightmare.