1. Epcot Center is not supposed to have princesses. Epcot was designed as a permanent World's Fair...it's core mission is to let visitors better understand the world around them, through both science and other cultures.
2. They tried making Epcot more "Girly" back in the early 90s.
It was a disaster.
3. I take issue with the notion that DHS doesn't have enough "for girls", since the majority of attractions there have a universal fanbase. Girls like Star Wars, too, you know. (just ask
@StarWarsGirl95) They also like Aerosmith and Toy Story. The Tower of Terror has universal appeal as a haunted house/thrill ride. Other than that....the shows are evenly split. Guys favor Indiana Jones and Lights Motors Action, while girls are going to gravitate towards Beauty and the Beast and Voyage of the Little Mermaid)
Sure they could always do a bit more (perhaps a new set of LMA movie cutscenes with a female agent, played by Danica Patrick
?), but as DHS stands, it's pretty geared even for everyone.