The Nephilim Protector is a rather limited model. It has no ranged ability and is also pretty blah in melee with MAT 5 and POW 12. It's job is to take it to the face, either with Shield Guard or blocking charge lanes. And on the occasional time you run into deadicated knockdown his animus can protect you.
The only warlock I have found that I'm willing to take it regularly with is pThagrosh. Because of Fog of War and Death Shroud, once you put Tenacity or Spiny Growth on the Protector it can actually stand up to enemy damage. At ARM 20 (with Spiny Growth) at range he can take a few big hits, and at DEF 15 ARM 21 against charges (Set Defense + Tenacity + Death Shroud) he can actually get in the way and block the charge lane to a heavy without dying.