When I first saw the preview/trailer for this movie, it made me think of the Hunger Games, as where both Katniss and Meridia are good at shooting arrows. But thats really the only thing in common between them, other than the fact that they really don't want to get married to anyone.
Also, when I noticed Meridias red hair I though about Ariel. I was wondering if they were trying to make a new princess to show off their red hair.
But the thing about their hair are the styles. As seen in the movie, Ariel doesn't have curly hair. It seems as she has straight hair, with wavy bangs.
On the other hand, Meridia has curly, bouncy hair that isn't straight at all. Also, she does not have bangs.
Another thing was the background. You may think it is a new background, but look closely. If you have seen the Hunger Games, you can see that the inviroment looks likes the inviroment in The Hunge rGames on a rainy or cloudy day. I wasn't sure about this, but I figured they needed to make it seem more real.
I also noticed the relationship between Meridias parents are similar to Ariel's relationship with her father.
In the movie, The Little Mermaid, Ariel's father doesn't want her to be with a human, and in the movie Brave, Meridias mother doesn't want her to fight and get married. Maybe they switched the relationships between their parents up.
Also, in The Little Mermaid, Ariel's father turns into something puny, as where Meridias mom turns into something powerful and they both were turned into those animals by a witch.
This is what I noticed