Romanticism, in Europe and in America, was a rebellious response to the Age of Reason, a time of intellectual and industrial development in both continents respectively. Because of this, romantic authors rebelled against anything reason/logic related. They were all about the following four characteristics:
1- Feelings
2- Love for nature
3- The rare and unknown
4- Individualism
Taking this into consideration, we could say that tradition and rational thought were not part of Romanticism.
In relation to the use of believable characters, this really depends on what believable means to you. Were characters more humane? For sure! Where characters more realistic? Not necessarily, for two reasons.
One of these reasons is that realism was still not developed. The other reason is that Romanticism gave authors room to play with their imagination, so they made up a great deal of characters of all sorts; demons, angels, people with superpowers, etc.
