It's where the pursuit of a dream was replaced with a job. The problems began when Po was raised to the supreme position. Po's power was in finally letting himself pursue the dream he's been having on his own for so long, and in how a true dream can overcome any obstacle in its way. First film's Po was so great because he was a classic 'loser with a dream' type of character: confined in his bleak reality but refusing to accept his destiny. The villain's complexity became the foundation on which the rest of the story could develop. So it's no wonder that my greatest wish for every next KFP movie was to have him back somehow. One of the reasons behind the first film's excellence was Tai Lung, a character so intense, conflicted and deeply rooted in the history of the KFP universe, that his story managed to combine the vibes of two great confrontations: Obi-Wan vs Darth Vader and Darth Vader vs Luke. The same rule actually applies to just about any story with some kind of confrontation, with the best of such stories having villains which you even want to relate to. As a certain character once said, a James Bond movie is only as good as the villain.
