Thanks all for your input. I bit the bullet last night and went back to Nagrand (like the ambience there ) , took about an hour or so to ding 70 doing the kill quests and also killed Durn for kicks. Now the 3 lowbies are at 20% into 70 and so should be fine to continue NR questing.
In most cases I like to just push through the quest grind and hit 80 asap, if I do a dungeon here and there I want it to be as painless as possible, if I do it a few levels up from the requirement I am thinking it should be similar to doing the heroics in some epic gear, but not tested that theory yet :P
I have cold weather flying on all my team and also have the BoA trinket on the shammies to help a little with spell power.
Again, thanks all for the input