In my opinion, I think that this is probably the weakest of the franchise. There was too much recycling done from the past films, the newer characters are really lame (except for Sid's grandma, who is absolutely hilarious), and the subplot with Peaches wanting to join the "cool" group is so unbearable to pay attention to, that I want to claw out my eyes and ears. However, the jokes are hilarious (a lot of it comes from Sid's grandma), the animation is impressive, Scrat is still pretty fun, and I guess there was a couple of times when I was biting my nails with anticipation.
Educational value: The film is about Pangaea (the Continental Drift), which may tell one or two things to children, but don't watch it for education. The movie says it was caused by Scrat, falling into Earth's core (without incinerating or getting crushed by great pressure at all), running around in it, and that somehow caused the continents to split.
Positive role models: Manny will stop at NOTHING to get back to his beloved family.
Violence and scariness: Of course, some cartoonish violence from Scrat; Captain Gutt is named Gutt, because he uses his claws to maul people to death; some of the pirates may look creepy to younger kids; a couple of gripping scenes where favorite characters have near-death experiences; during Manny, Sid, Diego, and Granny's journey back home, they are attacked by very scary-looking sirens, that take the form of the gang's desires, to lure them over, so they can kill them; Scrat also has an encounter with the sirens, and he almost dies, as well; the sirens make one final appearance in the end, where the trick Captain Gutt into coming to them. He falls for it, and they presumably eat him (off screen).
Well, it's an Ice Age movie, so you know for sure that there will be plenty of sex jokes to go around. Also, in order to lure Sid and his grandma to them, the sirens take the forms of super sexy sloths. Granny's siren closely resembles Fabio.
Consumerism: Keep in mind that the Ice Age films are one of the highest-grossing franchises in the world. After seeing the film, kids would most likely want to buy Ice Age video games and figure sets, as seen in stores.