With the Group B departures gone and the Group C's happening soon, there will still be a few more upgrades that will happen, but they will be sporadic. The waves are basically over, and for the most part any upgrades from this point out will largely be because of current JETs who break contract (which is not necessarily a sign that they were in a bad place; many break contract because of health or job reasons, or because they cannot handle the change in countries or distance from their families).
Upgrades will continue through the rest of the fall and into the winter (technically the cutoff is mid-December, but I have seen upgrades take place in January and even February before, so that is a possibility). If you are still interested in being a JET and have the flexibility to stay on the alternate list, it is a good idea to do so. However, I would recommend looking into applying again for next year as well. Right now is a key time to start getting your documents together and plotting your application strategy. By that, I mean considering the things you have done in the past year that need to be updated (Did you graduate? Did you get a few more months of volunteer or work experience in?). Also, it's a good idea to plan your statement of purpose. The SOP is absolutely crucial, since it is the one place where you can actually stand out and show personality and commitment. Now that you know what the application looks like and how the interviews tend to go, you have a lot of experience that should hopefully help you with next year. Having made it to the alternate stage this year is no guarantee that you will be as successful next year, though, so I strongly recommend being just as careful in putting your new application together as you were with the previous one.
For those of you comparing rates of upgrades this year to last year, that is not a fair comparison. Last year was an unusual situation because of the earthquake. In some locations, there were a lot of shortlisters dropping out, which meant higher than normal numbers of upgrades. Also, some JETs decided to break contract, which also led to more upgrades. This year's rate of upgrades is much more in line with previous years'. Unfortunately, JET's popularity and the high number of well-qualified and enthusiastic candidates means that we will always have at least a few alternates left over at the end of the departure season. That does not mean that you are not capable of being JETs; it simply means that for whatever reason, your scores were below the cutoff line for the short list and that either your score was not high enough to be one of the alternates chosen early for an upgrade or that your application did not exactly match specific requests that a Contracting Organization may have had (such as to have a driver's license or to be from a sister city).
Best of luck for a future upgrade and, if you decide to apply next year, with the upcoming application cycle!
