Pope Francis has been a strong critic of the income gap, the dark side of capitalism and selfishness. The last two popes had similar views, but this pope has more credibility. He seems more humble, himself, in things like his choice of pope mobiles and clothing. Also he is less pushy about the church dogmas that aren't that friendly toward birth control, gay rights and feminism. The other popes were more pushy on those dogmas so they ruined their credibility among liberals when it came to what they were saying about things like poverty and greed. What this pope says resonates better with us liberals creating more of a resounding chorus. The other popes might have tried to sing that tune, but it was more cluttered with emphasis on parts of the dogma that would turn the rest of the liberal choir away.
Also, the past two popes came at a time when the Catholic Church was besieged in the midst of the priestly sex abuse scandal. That scandal is probably starting to wind down now. It clouds the credibility of any stand that the church takes on ethical issues, but even that ugly black eye seems to be starting to recede into the history books by now.
On the topic of gay rights and population growth, the pope is still not willing to drop old ideas, but he does seem to speak more softly on these things. Using the concepts of grace and forgiveness, he puts out a welcome mat to more diversity of people and dialog. This is also an important step forward. Less of the witch hunt mentality that pope Benedict was accused of.
Personally, I still think it will be difficult to solve climate change unless we address the population problem. Even this pope has said he doesn't expect us to be reproducing like rabbits (I forgot the exact quotes), but church dogma puts a lot of obstacles in the way of new thinking on sex and family issues.
I still think this pope has taken many steps in a good direction and, for the most part, has been a positive influence in the ongoing discussion. He does have a kind heart. Change is often step by step.