2013 Fairytale Designer Collection
A lot of people were confused by the fact that Mulan and Pocahontas being taken up as princesses but there explanations online about why they have been taken up as princesses. You are right that Mulan was never a princess or close to being one but she was honored for her courage and what she did for China. Pocahontas, well she was the daughter of the chief which in a sense is similar to a princess. That and my guess is Disney wanted to bring a bit of ethnicity to the princess line as they wanted to capitalize on the merchandise.
Merida came out after the designer doll release and was only confirmed to be inaugurated around the end of last year. So if they really wanted to add her to a line then she could fit in the so called "heroines" line. Don't forget she is still technically part of the princess line up until the inauguration which I believe happens at the end of the year after the release of the next series of LE merchandise.
In my opinion I think disney will be moving away from the designer line, or even the dolls series (apart from the LE dolls). Either that or they will listen to what the die hard fans have been asking for and release designer dolls on the other female characters that are not part of the princess/villain line up.
Merida came out after the designer doll release and was only confirmed to be inaugurated around the end of last year. So if they really wanted to add her to a line then she could fit in the so called "heroines" line. Don't forget she is still technically part of the princess line up until the inauguration which I believe happens at the end of the year after the release of the next series of LE merchandise.
In my opinion I think disney will be moving away from the designer line, or even the dolls series (apart from the LE dolls). Either that or they will listen to what the die hard fans have been asking for and release designer dolls on the other female characters that are not part of the princess/villain line up.