First of all, it was unbelievably clear that this movie was trying indirectly to give a portrait of the life of Wonhyo. (Perhaps if I were not taking a course on Korean Buddhism then this may not have been so obvious, but as it stands now the comparison to Wonhyo was easy to see.) Looking up the word 'mandala' in my Korean-English dictionary, it read "Buddha's picture," and this movie seemed to me to be a question of what being a Buddha really was. In other words, given the contradictory images of Wonhyo that we know, is the image of Wonhyo as a (pardon the cliché) 'mad monk' - i.e. the image of a Buddha as a diamond in the rough - correct, or was he actually just a monk with a particularly poor ability to follow the vinaya?
It was interesting, although not unexpected (given the place of Uisang in history, and given the cliché nature of the situation) to see the juxtaposition of Jisan and Pobun as monks. The duality of the two was thoroughly evident - one disgraced then exiled by the sangha, one a member of the sangha; one epitome of what the vinaya instructs against, one attempting to follow the vinaya as best he possibly can; one fully certain of the dharma, one struggling to accept it and to use it to view the world. However, the part of film regarding this duality that I could really appreciate was that, unlike the texts we have read so far, this film made it a point of emphasis that these two "opposites" were not really the extremes that it is so easy to categorize them as.
As could be seen from the constant questioning going on in Pobun's mind, he was not so sure of the precepts as he made himself out to be. In fact, it almost seemed that if he were in a power struggle with his will, and that the main reason that he did not stray from the vinaya was for fear that if his will wavered in one problem, it would bend and fall at the mercy of others. So, he was in effect just trying to keep himself away from attachments for fear that he would indulge in them. (However, in doing so he created a great degree of attachments - e.g. to the vinaya - and aversions - to anything that the vinaya taught against.)
With respect to Jisan, he was not such the fool he was not such the cliché mad monk he was made out to be. From the very start, Pobun vouches that Jisan is a monk, asserting that no fake monk could chant sutras as well as Jisan did. When it comes to blessing the new Buddhist temple in the mountains, Jisan knows that one has to be of rank in the sangha to do that, and he admits that he is not. These and a few other examples lead me to believe that, in fact, Jisan could follow the vinaya to the letter, but he chooses not to. My guess is that he does this believing that the Buddha is not found in the vinaya, but that the vinaya is found in the Buddha. In other words, if you are on the right path, strict attachments to the vinaya are just like any other attachments, and what makes one a Buddha is what is change inside of him, not change through external regimens.
So, dismissing the concept of an extremist view of Jisan and Pobun (and Wonhyo) as members of some polar opposites club, I would say that the intention of the film is twofold. On one hand, these ideas are intended to dispel the notion of Wonhyo as some mad monk who has some frenetic method to his madness. More likely, he may have done some crazy stuff, but it was not with regularity that practiced it; he did it some of the time, just like everybody else. On the other hand, I think that this is an intended message about all of Buddhism, that your method - whether it be going left or right, being celibate or promiscuous, being sober or drunken, being a solemn introvert or an easygoing extrovert - is not the important thing. The important thing is not the vehicle in which you drive but the destination at which you arrive.