Despite Tiana merchandise flying off the shelves, The Princess and the Frog was a (relative) failure for Disney, which caused them completely change their marketing strategy for Tangled. Their reasoning: the movies only appeal to little girls. Despite Rapunzel being an official Disney Princess, this was completely downplayed and her movie was made out to be a Shrek-like 3D animation romp. Since then, Tangled has done great at the box office, and Disney has said that they will not stop doing fairy tale movies.
Newer Than They Think: Despite the fact that Disney has been making movies featuring princesses since 1937, and featuring the princesses on The Merch for their movies for years, the Disney Princess franchise itself was only introduced in 2000; that makes it younger than other Disney franchises such as Baby Einstein and Toy Story.
Original Character: Technically Merida is this to the franchise, since she is the only heroine not based on a prexisting source.
At least six new shorts were prepared for a direct-to-DVD series called Disney Princess Enchanted Tales, but the ban on Direct-to-Video Disney sequels killed the line after the first volume. As a result, only one Aurora short and one Jasmine short became available, and the ones for Belle, Mulan and Cinderella (as well as a second one for Aurora) might never see light of day. The original DVD of Cinderella III: A Twist in Time contained a preview and a trailer for the unreleased Aurora tale, that show just enough clips for fans to piece together the storyline.
A Spear Counterpart called Disney Heroes was planned to focus on many of the male protagonists (as well as other heroic characters like Robin Hood and Peter Pan) but fell through when the few action figures released sold poorly.
Swan Lake, Bluebeard, Rumpelstiltskin, Aida, and The Love For Three Oranges were each going to be made into a film at some point by Disney (although the first was eventually made into a non-Disney animated film, The Swan Princess). Maybe their heroines would have been in this franchise.
Giselle from Enchanted was going to be given Disney Princess status as well, but Disney abandoned the idea when they realized they would have to secure life-long rights to the image of Amy Adams, Giselle's actress. Not to mention Aida got a Disney-supported stage musical.
There have been occasional instances of heroines being shown in official merchandise. This includes Alice, Esmerelda, Megara, and Jane. Tinker Bell was also to be included, but she eventually got her own franchise, the Disney Fairies.