I think beauty in basslines comes from a sense of melody - not just defining the chords and rhythm by moving through the root notes, but finding a tuneful line that is compatible with, but different from, the main melody of the song. It's counterpoint, basically, so a study of that would be a good starting point.
My perception is that to feel beautiful, the bass needs to define a more complex chordal form - getting some seconds, thirds, sixths and sevenths in there as well as the 1-4-5. That means understanding harmony to some extent.
I think a study of basslines that feel beautiful would also pick up the use of ornaments and incidentals - extra little details that highlight parts of a melody and adjust the harmony temporarily.