We can look at a wall of fame in at least two ways.
In one sense, it can be a way of honoring people who have done important positive things that have improved the world. On this score, it is harder to say that Luther belongs since his main claim to fame is the creation of Lutheranism. If one believes that Luther’s theology was superior to that of the Catholic Church, then Luther did something that improved the world. But this is something of a subjective judgment.
In another sense, a wall of fame is simply for people who are famous; those who have done important things. On that score, there can be no doubt that Luther belongs. The Protestant Reformation was one of the biggest events in the history of Western Europe. It led to religious warfare between various countries and was one of the major causes of conflict for the next two or three hundred years. It also, arguably, helped to bring about the ideas of greater democracy and human rights. Max Weber argued that Protestantism brought with it a work ethic that helped to make Europe and its offshoots like the United States very wealthy. For all of these reasons, Luther is a very important figure in world history who did things that ended up changing the world in important ways.