We REALLY don't want or go down that road. As bad as Terminators are, they really wouldn't stand up to Cybermen, Movellans, or Daleks.Given how badly The Doctor has been fouled up the last few years, I'm not sure inserting him into the Terminator Universe would result in 'He's the Doctor and he's here to help'.
Although ... the new woman-Doctor could serve as a decoy for Sarah Connor ...