I can't say much to this but it does seem that eventually you will need to decide where you want to stay permanently. I have heard a lot of cases where your wife would want to stay in Japan. If the environment of Japan is right for you, I think it should be completely fine for you. Try your best to adjust to the culture. The big hurdle of being able to take care of yourself and your family is sort of already considered. Although do try to find out if you are allowed to do the kind of work you will be doing with your spouse visa. As long as you pay your taxes and don't break any laws, you should be able to to eventually get permanent residency based on being with your wife.
I should mention (although you probably know), the ecology of okinawa is very different from main land japan. It has a lot of influences from china. The political stances of the people there tend to be a little different from the general mainland. Also I have even heard that some don't even consider themselves japanese (although not sure if this is really true). From what I have heard, okinawa is small so everyone in the island will know about you pretty quickly after you have arrived. So if you are a city boy, then it might be a bit of an adjustment, but I think if you are open minded and willing to try to adjust, you should be fine. I have never been to okinawa so this is mostly based on friends that have traveled there or what I heard in interviews or online.