I don't think that Luther's writings demonstrate that he was emotionally imbalanced at all. That's a cheap shot at best.
I think that Luther's writings reveal a man struggling with the realization (in his mind) that much of what he had been taught and had strongly believed was in error and even corrupt.
Luther was one of those unique individuals who had the courage to stand up and tell the emperor that he had no clothes, but summoning that courage would be emotionally difficult when the emperor is the RCC. It's hard to argue that the Roman Catholic Church is not in many ways designed to discouraged those unique, courageous individuals like Luther.
I also think that every person who calls himself a Christian should thank God daily for the Protestant Reformation. I shudder to think what the RCC would be like if Luther had not been born.