Also consider the fact that sometimes, /war is just plain more fun.
I don't deny the power of /nin, but sometimes /war is just too much fun to pass up. My ls still kites Kirin, since TP burning would involve making half our ls sit out (the half without a heavy melee job or BRD at 75), and I'd rather go /war to that. Wyrms, I /nin and KS99 I /nin. For the lesser sky Gods, why bother with /nin, when you can rape them in a minute flat, regardless of what your tanks are subbing? Might as well take the hits head on and have some fun.
For Limbus I go /war, but for Protos I go /nin.
For Salvage I /war, but it took me a while to find someone who'd even let a PLD in, so I haven't really had any experience with the tougher NMs in there etc.
For Assault, I always /nin in DD setup, but that's mainly because I Assault static with a WAR and a MNK, and since the mobs are all DC-VT (in the Assaults that do involve fighting, that is), I don't really even bother to try. Might as well just let the BB MNK tank, and help deal some damage.