Questions for my 2nd trip to Japan

I'm finalizing my itinerary for my 2nd trip, this time I am focusing mostly on southern Honshu. I have total of 17 nights (18 days). Here's a breakdown.

• 7 nights Osaka as base (Osaka expo, day trip to Kobe, Naruto theme park in Shikoku)

• 4 nights Hiroshima, Miyajima (first day is day trip to Himeji coming from Osaka)

• 6 nights Kyoto (last full day split between Kyoto and Osaka on the way to the airport)

I've visited Kyoto and Osaka last year, but I decided to come back and give Osaka a chance (I only did a day trip last time). Plus there is a Pokemon Go event and the Osaka expo so why not extend my stay. I intended this trip to be less chaotic and more relaxed than last time.

Questions:

• I was considering adding USJ, but I am only interested in Nintendo world, is it worth the time? I've never stepped inside Universal studios in Singapore despite going to the area multiple times, so I have no reference. I did visit DisneySea last year, and despite not being able to ride the popular rides, I ended up enjoying just walking around the park and eating the snacks.
• Would you recommend staying one night in Miyajima? I put the nights in Hiroshima coz I personally don't want to hotel-hop too much, but I could adjust one night for Miyajima.
• I've been to some of the spots in Kyoto, but I missed out on some temples like Kiyomizudera, and Uji as well. Any notable spots near Kyoto that I should consider? I am planning to go to Kurama hotsprings as someone suggested in one of the posts. Maybe Lake Biwa for some relaxing day trip.
• Should I consider Kanazawa for day trip? While it's accessible despite the considerable amount of travel distance, I don't want it to end up how I felt with doing a day trip to Osaka like last time. I have this notion of staying at least two nights at one place to get a good appreciation. (Although I did mention doing a day trip to Kobe and Himeji.)
• Can you recommend any hiking spots around Kyoto? It doesn't have to be very complicated hike.

Thank you!