The original Shrek was released 9 years ago, so the kids who originally fell in love with this goofy ogre are now finishing high school, going to college, or mooching off of their parents. They probably don't really care about this franchise much anymore. Kids new to the series probably won't be interested in coming into the story so late. So it makes you wonder why Dreamworks would even bother making another sequel.
I shall call this film "It's A Wonderful Shrek". Our "hero" has become domesticated with a wife and three kids, but longs for the days when he was feared. He makes a deal with Rumplestiltskin that he will trade one day of his life for one day as an ogre. Unfortunately for Shrek, his one day takes him back to the day he was born. In this alternate world, none of his friends know him, and things have changed for the worse. The only way to put things back to normal is with true love's kiss.
Wait, wasn't that the premise of the first film too? Yeah, it was. In fact, a lot about this film is recycled. Back in 2001, the original Shrek flipped nursery rhymes on their head and added pop-culture references that made the story fresh and new. 9 years later, the voicework in this film is still great (Antonio Banderas' Puss In Boots is still one of my favorite cartoon characters ever), but the jokes have grown stale, and the novelty has worn off. This is supposed to be the last Shrek film, and if it turns out to be, that's good, because this is one ogre whose time has passed.