I agree, the writers started talking about Shizune's family history being weird because of her deafness and then left it hanging. And FREAKING JIGORO is ridiculous, which they never explain. I guess he is just comic relief, but I think he negatively effects her route - it makes it very much less realistic and believable. You aren't going to have a future with a girl who's father hates you and is a butt.

Also, I think her route ended the worst (why most people don't like her route). All the other routes, either explicitly or implied, wind up kind of happily-ever-after, with Hisao and the girl having a future together. Shizune's just like...."I'm going into business....We'll all meet again sometime. Deuces yo"... It doesn't feel like they connect, or like she loves Hisao back.

I enjoyed most of her route, up until the last act when she gets all "busy with the student council work" and distances herself.