The Terminator is derivative yes, but mostly from two Outer Limits episodes from the 60's which obviously predated the DOFP story by over a decade. I can't help but think of T2 everytime Logan says, "I was sent by YOU" to Charles though. That line does seem pretty reminiscent of Cameron's work. I think we're at/have been at a point where current stories are just a melting pot of influences and influences OF influences.