We saw it opening night. Me, DH and my 17 year old daughter who is a Disney Pixar nut (she is an art student so this stuff totally floats her boat!)
The place was packed and there were many younger kids. When these parts you allude to started to occur, there were many in the theater having negative reactions. We saw a few leave (finally after several minutes of outright/crying screaming by their kids). At the end, there was a child way up front who was just sobbing. I would guess a 4-6 year old.
So yes, I would recommend it to older elementary kids, just so they understand whats going on and can deal with it. But like all Disney movies involving a princess (which she is) there is a "bad" guy element. For many kids this can be alarming. I do not want to give things away ..but will add a SPOILER ALERT that might make some understand why some kids were some kids were so alarmed.......these negative parts involve a witch, and scary stuff happening with the princesses Mommy. Kids probably have a hard time identifying with the Mommy part.
Please use your judgement and please do not make other movie goers suffer if your child needs constant calming down, talking to and discussion and chatting during the movie. I paid the same price to see the movie and that was not what I paid for (nor did I attend a childrens performance.) In 3D it would be more so. We never do 3D as I get motion sick at them.
Just because it says Disney, does not mean its preschooler safe. Do your homework and use judgement!
Best wishes.
ETA~ for us, with a teenager who is an art student, the art of it is a big deal. How realistic the water looks. That the characters actually BREATHE (this is a big deal in animation I guess). One scene where Princess Merida flumps herself down (in despair I suppose) on a bench/couch...you not only see her breathe, but you feel you could reach out and touch and feel the wool texture of her old time Scottish dress. Also the way the animals (especially the horse) looks so realistic, not cartoony). This is all a BIG BIG deal to us. This is a big reason we go see these movies. To appreciated the artistic advancements in them and thru the eyes of our artistic creative daughter who is a great authority on such topics. I love hearing her explain rendering, and frame by frame stuff to me!