Does anyone really like DiCaprio's performance?
I know that this film is probably hugely criticized for the casting of Leo as the historical Louis XIV, given that he had come off of Romeo and Juliet and Titanic and was looked upon as a teen heartthrob for those films. Still, I find it very seductive to see him dressed in that 17th century finery and that stern expression on his face that he absolutely embodied royalty.
Also, even though the king is meant to be the bad guy in the film, Leo didn't exactly approach him in an evil way, but in a very posh and vain manner that showed how laidback and refined he was about living royalty, rather than devote time to feeding his people. Most of the time, he acts sympathetic and understanding of people's wishes (even though he doesn't stay true to his word) and then gets sensitive whenever he feels betrayed. He's really just a guy who wants too much because he thinks its his right as king and becomes dangerous when he doesn't get it all. It's only after he realizes that Christine never really loved him and when he's betrayed by the Three Musketeers and his brother that he becomes more openly hostile and wrathful that he no longer cares what will happen to anyone. I think Leo knew how to go into those areas since a young actor at that time is good with bringing out his immaturity and spoiled attitude when he's playing a character who hasn't entirely grown to manhood and just expects everyone to give him what he wants.