Yet another animated film with a broken story.
It makes absolutely no sense that a relationship is set up between Po and Tigress--a relationship necessary for Po's growth--only to have it completely disappear for the latter half of the movie. Instead, we are led to believe that Po somehow magically changes by remembering where he came from. But wasn't that his problem in the first place, a problem of gross denial? You don't overcome a problem by continuing to engage in it. That's not how story works.
Main Characters can only meaningfully grow when they are challenged by another character who approaches similar problems in a different manner. By seeing an external reflection of themselves, the central character of a story reexamines the issues plaguing them and then decides where to go from there.
Both Po and Tigress are orphans, and as such, are primed for the classic You and I are both alike type of scene present in complete stories. Yet, beyond their initial conversation on the boat and their awkward hug in the prison, they don't share a single word. One hopes and prays that at the end, when they get blown out to sea, that they'll at least say something to each other, anything that would foster some kind of meaningful character growth. Instead, they simply look at each other and nod.
Why are they nodding?
Furthermore, how are general audiences supposed to recognize or remember that Tigress was a lost orphan just like Po? It was touched upon in the first film, but one shouldn't assume that audiences automatically remember the motivations of a character in sequel. More importantly though, how did engaging in "hardcore" kung fu help Tigress grow beyond her own personal issues? And how can that approach help Po grow?
These are the types of questions that would be answered in a complete story.
The fracturing of the relationship between Tigress and Po is the reason why the film feels emotionally empty or "light". Sure, the scenes with Po and his adoptive father are nice, but those scenes are tied to Po's issue of who he is. Stories need that relationship tangential to personal issues in order to mean something and to foster growth within the Main Character. Besides, the final final scene completely erases any goodwill engendered by Po's release of angst.
The reason the film feels broken in two logistically is because of Shen, his apparent goals (or lack thereof), and the actual problem of the story. The arrival of mechanized warfare is the problem of the story. When it is destroyed during the initial meeting between Po and Shen the audience is left to wonder now what? They soon learn that there are even more cannons (a surprise that only breeds distrust within the audience), and that Shen has his sights on destroying China.
But if that was his initial goal, what the heck was Shen waiting for during the entire first Act?
As a result, the problem shifts from a purely situational one dealing with the arrival of mechanized warfare to a problem of simply stopping a mad man from leaving a harbor. Po may have defeated Shen in the end, but the problem still exists--cannons and the means of producing them still threaten kung fu and China.
In short, a different problem is resolved from the one initially created by the Inciting Incident. As a consequence, the film is broken into two separate, lightly explored half-stories.
That said, the production design is astounding and the 3D sublime. A visual feast devoid of any appreciable meaning.