You probably wouldn't need dual dreams, since psn usually takes them to 1hp, the aura damage from 1 dream would be enough. But fire golem would work just as well and you wouldn't need to sacrifice the skill points.
Most pvp nova necros try to hit either the 75 or the 125 fcr bp. Most choose to go max block. You can't effectively do either of these with dual dreams...and to make up the fcr you'd have to sacrifice a DWeb in the weapons slot for a a HOTO or Wizzy....drastically reducing your damage (since you are losing as much as 8 skill points and as much as -55 to enemy poison resist).
While dual dreams sound like it would be aweseom, in practice it is much better to just plan on getting that last hp with fire golem, teeth, spear, fire wall, etc.