This is a great question. There are so many people that you can mention, but If I had to pick one person, I would pick Martin Luther, the German Reformer. There are three reasons for this choice.
First, Martin Luther was the person who started the Protestant Reformation. To be sure, there were people before him who protested against Catholic practices, but in the end, he was the person that put things in motion. The story of Protestantism since Luther has really changed the world.
Second, from a sociological point of view, there is an explosion in religion in our world, whether we know it or not. For example, in Brazil alone there are over 50,000,000 protestants. South Korea is a protestant nation and it continues to grow in its economy (like Brazil). Even China now boasts of over 100,000,000 protestants, not to mention America and its growth in protestantism as well. From this perspective, we can say that Martin Luther is sort of a father figure.
Finally, Luther translated the Bible into German from Latin. This move to the vernacular made way for the Bible to be translated into other language as well, which made a huge impact.
In the end, one of the greatest issues our world will have to face is a religious issue.