Everyone seems to be dancing around the point here. Senses per se vary greatly within a population; some people have good eyes, some don't. Some people can hear well into the high 10 and 20's of kilohertz, some cannot. Some people can taste "savory", some cannot. Small is particularly variable; there is a woman who works for one of the coffee makers who is phenomenally able to discern between thousands of quirks in coffees. But the key here isn't really the senses, it's the processing that happens with their inputs in the brain. People are trainable, to a large extent, to be able to overcome deficiencies and use the capabilities their senses do have. With practice, people integrate the feel of a car sensed by the hands on the wheel with the sounds and sights of driving; most don't ever really notice, until they have to change cars. Cats (just Siamese cats? Can't remember; I read the article long ago in Scientific American) have a mis-wiring in their optic nerve which causes one segment of their vision to be transposed with another, but experimentation shows that the brain has compensated for it. The brain is very good at filling in gaps for things that aren't really there; most people never notice that there is a blind spot in their vision in each eye.
Those with missing senses have to learn to make due with what they do have, and the brain is marvelous at doing that. They also have 24/7/365 practice; with no days off. They aren't distracted by the missing sense. Everything is going for making what we consider remarkable use of the remaining senses. It serves to show us what most of us could probably do as well, if we had the right incentive.
