Unless you are running out of mobs, I don't recommend turning your back to proc. This is especially the case if you have TH.
When my group goes w/ a DNC we typically have a THF and 1-2 SAMs.
As I said, when I'm SAM/DNC I back tank to proc so if the DNC procs his/hers before me
we can switch mobs and I'll down theirs in 1 WS or so and move on while they fight what I was back proc'n.
That way the mob isn't chasing after me while I'm pulling another,
the THF is TH'n everything and throwing JAs as well.
I agree though, I wouldn't back tank on DNC.