I was pretty upset last night because I had a 55 minute queue as DPS (That's not why I'm complaining, I know I should go healer iof I want quick queues blah blah blah) and I got into a group that was on Nazgrim with 3 stacks of determination. Pretty PO'd that I only got last boss but whatevs.
We pulled the boss that time and like half the raid died to standing in axes and cracks. Next pull the off tank dcd right after the pull so we wiped due to sunder armor stacking. Finally got him down with 5 stacks.
I can't speak for the whole wing, but I feel like that boss had a pretty good difficulty. Once people gear up a bit and learn the strat more I think it will be fine. That being said I think the whirling axe thing hits for way too much. On my shaman (mail gear) it hit me for like 288k per tick. If I recall it ticks pretty fast and can therefore kill pretty much anyone in 2 ticks if they're even just a bit slow on their reaction time.