This is a good question, but one that is fraught with personal opinions. However, there are several important points to address.
First, we live in an increasingly global world. Hence, a social study curriculum should reflect the diversity in the world. For this to happen, teachers should teach not only about other societies, but also introduce categories of thought that are non-western. A teacher may even want to question Western assumptions. This will be a challenge but essential.
Second, with the idea of a global village, the world is getting more competitive. For this reason, the curriculum should be be one that emphasizes critical thinking. Too much education is based on rote memorization. This point is not bad, but more can be done in the area of critical thinking by comparing different points of view, which should be possible to do by examining other cultures.
Third, a curriculum that uses technology would be helpful as well. The reason for this should be obvious.