I rather not frown on it.
There are many legitimate reason for waiving from Jury duty, for instance maybe he was victim of a crime, maybe he has PTSD, maybe he has serious mental issues that may not be able to give a fair verdict, and so on. For me, I would have to request waiver, not just because of Deafness, it is because I can't sit for too long due to neck injury. But hopefully in future I may be able to sit and serve my country.
Perfect example, if a candidate for jury duty had traumatic accident caused by drunk driver years ago, and the defendant was accused for driving drunk, will that candidate be able to stay neutral? If that person can't, then the trial will end up mistrial.
The only thing I would frown upon is if one try to get waive just because of Deafness.