The Reformation began with those Catholics that thought reform of the corrupt and greedy clergy was possible.
For hundreds of years the clergy as a group was a moral sink hole of concubinage, whore mongering and the selling of their offices.
As long as they could engage in simony on a wide scale all the half hearted edicts and councils were worthless since the hierarchy loved the income they could skim off the top.
If you wish to talk about motives in the Reformation first spend some quality time with the history books.
People start all kinds of things over the best of motives. Look at the Bolshevik revolution in Russia. The point is to determine who has the power, why they want it, why they have it, and what are they doing with it.
Look at the novelties developed over the last 500 years, with each innovation being stranger than the last. Is there any doubt that Jim Jones (The People's Temple) or David Koresh (Branch Davidians) was a logical and expected development of the thinking that came from the Reformation?
Regarless of what the Reformation was protesting against, a separate topic, the results of the Reformation have given us the LDS, Jehovah's Witnesses, and Heaven's Gate.
If you wish to talk about motives in the Reformation first spend some quality time with the history books.
Already have. We can speak to the motivations of certain individuals, we can speak to the motivations of those that made it succeed, we can speak to the rewards of those in power afterwards, and we can speak to the modern results of the Reformation.