I suggest you get some pretty coffee table books, compare the locations, and decide for yourself. My choice would be to rent a car in Takayama and drive for two or three days - taking a scenic route through Shirakawago and perhaps as far as the Noto peninsula - before returning the car in Kanazawa. But others will say that Hokkaido's unparallelled national parks and seafood are the bizniss. YMMV.

Regarding your plan --

(1) 7 nights in Tokyo at the start could be cut back.

One suggestion that I have is to spend a night at an onsen ryokan somewhere rural at this early point in your trip. If it turns out that you're really not that keen on the ryokan experience, you can change arrangements for the rest of your trip. At one point you mentioned Izu - This thread has links to ryokan on the Izu peninsula and other locations within easy striking distance of Tokyo.

http://www.flyertalk.com/forum/japan...n-all-one.html

So ... My suggestion is that you could stay a night or two at the MO. Leave your heavy luggage at the hotel and go on a safari to Izu, or Nikko, or Nagano, or Hakone. See how you get on at a posh onsen ryokan - adjust reservations for the rest of the trip if necessary. Then go back to Tokyo for a night or two before heading to Kyoto.

(2) I don't think you need stay in Nara, Kyoto, AND Osaka. They're all within easy distance of each other. 12 nights in the region could probably be cut back to 5-7 nights. Use Kyoto as a base. But I'm not sure I'd do 5 nights at any ryokan. YMMV.

(3) The hotel in Fukuyama looks splendid but everywhere you're staying is going to be splendid ... so I don't know if that's a reason to stay here.

(4) Hiroshima could be cut to one night IMHO. Particularly since you're staying a night or two on Miyajima.

(5) Miyajima Grand Hotel Arimoto looks like an OK hotel, but not really on a par with some of the others in your list. I think it's a big tour group place - and there are a lot of those on Miyajima. You will definitely need to book WAY in advance for Miyajima if your visit coincides with the maple trees turning color. (early Oct).

BTW "Hatsukaichi" is kind of "street level" in the hotel address. Better to refer to this location as Miyajima.

(6) For Kyushu, I think QShoeguy can point you to the best onsen ryokan.

(7) I'd skip Yamaguchi if I were you.

(8) I'd skip Sapporo too