Then what redemption is there to take place during the meat of the movie?
If the movie is about him overcoming his social isolation, then Shoko's deafness is a distraction from that story that takes up a huge chunk of screen time. That can't be it. But the ending leans that way.
I know Japanese movies don't do Oscar Bait, but it kind of feels like Shoko's deafness is a kind of pandering to make audiences feel like they're partaking in a minority culture.
Comments elsewhere say that a bunch of stuff got cut that made Shoko a bigger burden on her family.