These sound a lot like the rationalizations used to justify why death is a good thing.

Actually -- the senses we use to shape our map of the world in a very strong sense alter the ways in which we understand the world. It has long been demonstrated that in patients who lack a specific sense, the neural mass normally dedicated to that sense begins to "bleed over" into the remaining senses, giving them more 'processing power' than would otherwise normally be the case. What this, in turn, means is that the perceptual world of a deaf or blind person is very strongly different from the one that we who have all five senses would otherwise understand or know.

What does all of this imply? The deaf truly perceive the world in ways that we who have all of our senses cannot today comprehend, in any true sense -- though we can extrapolate from considering cases such as color-blindness; I can imagine that to a deaf person I am effectively color-blind to a whole range of visual depth that I can no more know than could a profoundly color-blind person 'know' the reality of red and green being profoundly separate colors.

In restoring hearing to such a person, if we are to truly argue that such a thing would be solely augmentative in nature, we should endeavor to ensure that such depth of perceptual capability was not lost in the process.

As a diagnosed autist, I very often wonder what it would be like to be what many of those of my condition refer to as "neurotypical". But I definitely would never want to live my life as 'one of you'; I am quite proud of the insights and demonstrably variant modes of thinking my condition has granted me.

As a transhumanist, I very often find that the notion of neurodiversity; of having the freedom to define for one's own self what one's cognitive processes should be shaped after, at any given time, is a more realizable near-term goal (morally, if not technically). It bypasses many of these problems.