Bevendre

People are free to like the characters they like, but others must understand that there are reasons for choosing one character over another.
People enjoy characters that they can relate to, not just that they find aesthetically pleasing.  Observation of a character’s few appearances, and extrapolation can easily result in a more defined character than those appearances and actions of a recurring character who has the same, unchanging role.
This is the case with Luna.  Her character is more developed in the first 5 minutes of the pilot than Celestia’s is through the bulk of the first season. Luna is a more relatable character than the infallible Celestia.