Was the Reformation Necessary?

A friend and I have been corresponding, covering lots of different topics, but lately focusing on the Reformation. A question came up. Did the Reformation need to happen?

I don’t like that question (and I told my friend so), because “necessary” and “unnecessary” tend to distort our view of historical events. The Reformation happened, and for many good reasons, as well as some very bad ones. Luther was right about the abuses of indulgences, for example. And his essentially Augustinian insight into the primacy of grace was surely right as well. But were those and other reasons “enough”?