Responses
I don't think he will ever do sexual assault cases because it will be too inappropriate for shonen manga, especially when his main character looked like 7 y/o (despite conan is actually 16-17 y/o). Not like murderer case are appropriate for kids, but rape is just ... too mature and will be harder to explain for young reader. I agree gosho should stepping up for the next cases though
Gosho makes the same things over and over and over. He should make more complicate and actual cases of murderers, rapes, these kind of things. And make a grand finale of this great manga.
PS: I think he should do a side-story about Heiji & Kazuha