A wristwatch isn't a limb. If you had an LED display implanted below the skin of your wrist/forearm and the display shone through the skin it might be considered a cybernetic implant, but a wristwatch fails the test of some sort of mechanical fusion with the organic.
A point that was omitted from your original definition. But I'm not sure that it ends up making more sense. An artificial arm, for example, may detect small movements in your shoulder stump (rather than being directly tied into nerves), and convert that into a range of motion that surpasses the average human arm. But, as there's no "mechanical fusion with the organic" (or at least, no more than when I press the buttons on this here keyboard), it would fail your definition of cybernetic.
This may be exactly what you intend, but such an arm seems to far better fit my ill-defined concept of "cybernetics" than would an implanted watch; that seems no more cyborgish than the RFID chips that people put in their dogs...
I'll go to the dictionary on this one:
cyborg |ˈsīˌbôrg|
noun
a fictional or hypothetical person whose physical abilities are extended beyond normal human limitations by mechanical elements built into the body.
ORIGIN 1960s: blend of cyber- and organism.
I was being a bit more specific because we were talking about artificial limbs. I'd argue that a greater range of motion doesn't necessarily translate to exceeding the capabilities of a regular limb if there's only one thing that's better and it's at the cost of other things. Something meets the cyborg standard when it replicates in all categories a human limb, and then does it one better. So same heat/cold/pain/tactile response, and then more range of motion/double jointedness and then stronger/faster/harder.
But a limb is a pretty high barrier of entry to cyborgishness. I seem to remember an old thread where we talked about a guy that had an RFID chip implanted that controlled various functions in his house — if he was playing music it would follow him via the speakers he had networked in all the rooms, the lights would come on when he was getting near the doorway, etc. Not a real big cyborg, but it's just a bit better than regular human.
Honestly I'm convinced that small cyborg is going to be pretty common within two decades, but we're never really going to go borg-like except for people with birth defects/accidents and that 5% of the population that will always do anything for the thrill of it.
Myself, I'd get a implant that did the time like I described, or one that acted as a password for my laptop. I'd probably wait a little while to get one that did VR, but only to make sure it works as advertised.
