Less of a continuation of the series and more of a chance for DreamWorks to show off some awesome CGI particle effects.
Although one could argue that the pacing and character development were greatly lacking compared to the previous features, that’s because this latest installment has a lot of information and secondary characters to compress into the same running time. The previous movies had interesting villains with somewhat tragic back stories while the latest antagonist, Kai, is mostly just an obstacle for the heroes to overcome and develop from. There was an attempt to tie the previous films into thematic trilogy but there was also a missed opportunity to tie them together in a more interesting way. By all accounts it appears that the creators of this project basically assumed that anyone who saw the previous movies would see this movie and decided to make it as flashy and as exciting as possible; but not much else.
There was also a fleeting moment of positive ethnic identity as Po meets not only his panda father for the first time but a whole village of pandas for the fist time. But this is a kids movie so who has time to appreciate something that unusual?