I feel like they're just adding disney characters from recent movies (like Elsa) just to promote the movies and I don't really like that

While I'm not a big fan of Merida, I don't think it's a bad idea. While Brave is a mediocre film, it still had great atmosphere and is still creative enough for Once Upon A Time to use for potential, a lot more than that stupid Frozen story ark did.

I like the idea (and I love the actress they chose), but only if they actually give her a significant role, rather than what they did with Rapunzel, who showed up randomly in one episode and was never seen again.

I just want Ingrid and Cruella back though. I love Merida though.

Merida is my 3rd favorite princess.

She may be my least favorite Disney Princess, but I'm pretty excited about this. Plus, she actually looks pretty in OUAT (I know that sounds shallow, but whatever).

I just don't care.

^ LoL This!
Also enough with the new characters! Can we just focus on the series core cast?

^ This. So sick of new characters; how about we develop characters we already have? Like Victor and Ruby... Or at the very least just focus on the main cast.