As our minds get more complex we start to appreciate deeper Disney characters like Meg. Disney is just very afraid to portray characters outside the 'pretty nice girl mold' as Princesses with the exception of Tiana.
Its fine to have a love story but its the same love story over and over. Handsome man meets beatiful girl, they fall in love. Beauty and the Beast and Mulan kinda breaks this trope but that is the only exception I can think at the top of my head.