If u save ur NS to when their all on low HP, its devastating. What happens to me usually, is using it at the beggining on a target that is far from his group. Well, without a proper early dmg, the ns itself no longer kill 1 target, because of their gear. Ofc im also working on mine, to increase spell and crit.

I really dunno how one can be so unlucky with the NS. Spellreflects and CoS, i pretty much see those, not as a counter attack, but as a defense, meaning, they cast it to save their ass's, never to screw me. Warriors are constantly using spell reflect, and rogues use CoS to get away...

I think ur giving away the method u use. If u contantly enter arenas and repeat a process of:
Usually I go for a purge, then a LB, then NS+EM+CL.
Ppl will learn it.
I use it mine at tottally random times, but trying more and more to use it wehn melee's have taken a fire nova or are low on hp.
It's not a matter of how to get it to work, its more like learn to use it i guess, and im also learning to use it, cause its the most devastating tool u have.