I think the fear of something like a terminator is a primitive, rather than a futuristic one. The idea of an unstoppable, unreasoning, unrelenting hunter dead-set on killing you is a pretty terrifying idea, and it doesn't really matter whether that entity is animal, human or machine. Since our ancestors regularly shared environments with predatory megafauna, it makes sense that this notion is fairly deep-seated in our psyche.
The terminators were never rogue machines, they were executing their orders from skynet just as a preprogrammed UCAV exdcutes commands from its human operators, or an ICBM is fulfills its guidance programming to drop MIRVs over a certain city (of course, Skynet itself was a rogue AI with the intention of killing all humans).
We've had things like ballistic missiles for over half a century, so the idea of a machine pre-programmed to destroy a target is nothing new. The idea of a robot being sent out with the ability to choose its own targets and decide whether to engage them is another matter. Melvin has a good point though; while it may be impossible to reason with a machine, in many situations one cannot reason with human attackers either (this does not make the Terminator particularly exceptional; if I understand correctly, it is essentially based on a pre-existing trope involving psycotic assailants and suchlike)
The uncanny-valley, 'human-imitating' robots really creep me out, primarily because they elicit all the negative responses an uncanny-valley inabitant should, but also because teams of people have worked really hard on something that has, to be entirely truthful, turned out rather poorly. And they also disturb me, of course, because nothing, not even a pile of metal and plastic, deserves to be that ugly... :uhh:
Yet you look at something like C-3PO, or R2-D2, a gold mannequin and a mobile dustbin, respectively, and they're not only relatable, but they're much-loved characters. Even a MER robot has little 'eyes' up on its camera mast and it's possible to sympathise with the perils of its far-away adventures despite the fact that it's essentially a box on wheels.
My advice to robotics engineers is to waste less time on trying to make their creations 'cutesy'.
