Did the French Revolution have a better legacy of solving social inequality and economic problems than the American Revolution and the Glorious Revolution?
The French Revolution, more than the other two, was specifically aimed at improving the lot of all of humanity rather than simply changing the group of people that were in power. The fact that it broke up the feudal system and made the transfer of privileges via noble birth illegal has helped to lead to the robust civil institutions and laws that govern France now. The break up of the large farms owned by nobles or the church led to the establishment of individual farms that were profitable for their owners, where previously the profits were almost all taken by the noble lord or the church or others through various taxes, etc.
The intense focus on equality immediately and significantly changed the political system in France. Though they did not immediately rule out the possibility of a monarch, a great deal of power was given to ordinary citizens and the effort to distribute power among the citizenry also led France to extend universal suffrage not long after.
Currently, social mobility and levels of poverty are lower in France by most measures than both the U.K. and the U.S.. France incarcerates far fewer citizens than either of them and also has a more effective system of universal health care if one looks simply at outcome based measures of effectiveness.
It is important to note that there are currently severe problems with the integration of refugee and immigrant populations in France that may present a new and different challenge. Some scholars have argued that the United States in particular does better at integrating immigrant populations than Western Europe which includes France.
But the previously mentioned factors of less economic inequality, a significantly stronger social safety net and more economic and social mobility by many measures would suggest that the French Revolution does indeed have a better legacy than the American Revolution and the Glorious Revolution.