Usually, when we hear about the "greatest" rulers in the time frame of ~1100-1700, it's because they did something prestigious for their country or their dynasty. Whether it's being part of a famous ruling family, having interesting political intrigue, financing expeditions to the new world, winning a key battle, etc.
I don't often hear about rulers that worked hard to insure the happiness of not only noble families, but also the common people. Did any exist? Were there any medieval rulers that would be considered "populist" by today's standards?
It can be difficult to characterize a ruler as "populist" especially by today's standards. While there are definitely numerous cases of popular Monarchs, many of them still had a preference for the nobility especially before the Industrial Revolution.
Interestingly, in the 1800s the concept of a "Popular Monarchy" started to take hold across Europe. This shifted the monarch's role from the leader of the state (ex. France) to the leader of the people (ex. the French).