I think that between your desire to go to grad school in a new area and your interests in working internationally - Fletcher would be the better option for you. While cost is a consideration, my understanding is that Fletcher has a phenomenal network and stronger international presence that would be more aligned with your career goals which I think would help justify the difference in cost for you. Additionally, Berkeley's network is much more based in CA so if you wanted to have a more varied network than Fletcher would be better for you and would expand your network tremendously.