Nixon was infinitely fair. It wasn't in the vein of JFK. It did use dramatic device to sum up information but it didn't throw everything on the wall to see what would stick like JFK kind of did with some of the information.
Nixon, the movie, presented the man as mentally and emotionally unstable thereby sort of allowing the audience to make apologies for the man's actions. Nixon was a weak man attempting to be strong, succeeding in some areas, failing miserably in others. Lastly, Nixon wanted to better himself by improving his standing in the world. He improved his standing but failed to better himself.
Personally, I really loved the line from Paul Sorvino as Henry Kissinger: Can you imagine what this man would be like had anyone ever loved him?