There are no simplistic answers to this question. The true answer comes from reading the quite voluminous written works that he left behind. I doubt too many on this list have taken the time to do so. Luther's theology developed over time. He was not alone in believing what he did. The abuses of the Roman Church were such that the stench could be smelled by anyone who had any idea of what real Christianity was. Luther was set on his way of salvation by Faith and Grace by his superior in the monastery. He was not the first to believe this, just one of the first that did not get burned at the stake by the Roman Church. Luther was also not alone in his beliefs during the Reformation. Some of the best educated men in Europe were in Germany at that time, and many sided with Luther. In the beginning, it was his intention to simply correct the most obvious abuses of the RC Church. However, once he was excommunicated, there was really no choice but to form another church. Had Rome not completely PO'd a large number of German princes with their continuous grab for money, Luther would have ended up like every other "reformer" before him, burned at the stake. However, Luther's religious objections to the legitimacy of the Pope's strangle hold on religion / politics gave many German and other Northern European leaders the "religious" backing to do what they had wanted to do for a long time; break with Rome. The term "Protestant" was a political term at that time and not a religious term as it is today. However, it would be safe to say that most of the secular "Protestants" had already broken with Rome in mind and heart, and used either Luther's beliefs or those of one of the other Reformers as the claim to the legitimacy of them going against the "Vicar of Christ" in Rome.
So, the Reformation is not just about the theology of Martin Luther. It cannot be fully understood without taking into account the other religious, scientific, and political things that were going on at this same time. Humanism was making strong inroads into the philosophy at the time. Rome's abuses were causing a lot of people to see religion is nothing other than a method of one man controlling many in the name of some cloud being that would zap them all if they did not do what the man behind the curtain in Rome wanted them to do. If anything, Luther still believed in a God that was both Creator and Savior, and he strove to return the Church to its Apostolic roots. History shows that he did not succeed, but there were a lot of things that were acting against him, too.
As to the relationship between the early Lutherans and the Orthodox, who knows where that correspondence would have gone over time had Constantinople not fallen to the Turks. The group from Tutlingen was only one group of German Lutherans. There were sects of Lutherans that were not so "Protestant" that may have benefited from communication with the East. Even Luther had written that he thought the Eastern Church had kept the faith of the Apostles very closely. But it was not Luther that corresponded with the Patriarch. To many Germans, the fall of Constantinople to the Turks was a sign that even the Eastern Church had lost favor with God, and it was now time for the "new" Church to rise. And lastly, what rose from the ashes of Europe after the long and bitter wars against the Roman Catholics and the "Protestants" bore little resemblance to Luther's original ideals. So little so that many groups of what are today called "confessional Lutherans" had to leave Germany and other parts of Europe to escape the changes made by the various princes and kings.
I certainly hold to the idea that Luther was well intentioned. It is the strong education that I received from Lutheran schools and Lutheran parents that started me on my way to Orthodoxy. It was Luther's own words about the "Eastern Church", and the Lutheran theologian's discussion of the "Fathers" that interested me in reading these Fathers words myself. I do not look down on Martin Luther, but consider my conversion to the True Church to be what he was trying for all along.