Not sure I understood what is your point here, but anyway, my point is that I don't see the use of GPS as "cheating" or a bad thing. Although, if you only rely on GPS for navigation, sooner or later you will be doomed.
You are misundertanding vision (as in vision algorithms) with human vision. We can only see in a limited spectrum of light. Cameras can use a much broader spectrum. My point is: it doesn't matter what sensor you are using, the real challenge is making good sense of the data you are receiving. We humans can see a water puddle with our vision, so the computer should be able to do it, it all depends on the intelligence is givem to it. As mentioned above, there is an additional advantage to robots, they are not limited to one type of sensor as we are. How do you drive through a sandstorm or through heavy fog?
That's because I did not define it. What I asserted is that the real intelligence [yet to be found] is in vision. You see, identify that there is a blob in a picture frame is already not a simple thing. Ok, in ideal conditions it is, but the real world is far from mathematical ideal. Light conditions change, lenses get dirt, etc. But assume you got that part nailed and you have the image nicely structured into objects. Now the real problem is to recognize what are those objects and what do they mean. For example, it would be nice for an autonomous tank vision system to identify bushes or soft objects from untraversable ones. I think all falls into the discussion if one day we will be able to have a strong AI, able to implement our horizontal knowledge (or learn its own) and common sense.
Cheers
Padu