I'm with you on the hearing loss part. It would be the simplest to replace with technology. Google style glasses with a heads up display, voice to text translation, (heck you would even care if they were speaking Mandarin Chinese), visual clues to other sounds like foot steps approaching from behind, your heads up triangulating where the gunshots are coming from so you know where not to go, little bird icons with tweet tweet, to let you know he robins are rock-in it out, little cat faces popping up by a food bowl meowing feed me feed me.
Hearing would be the easiest to replace via technology that we have today, the bonus of no hearing is you can sleep through all the noise all the others complain about.
!ENGAGE 15