(Obviously, full spoilers ahead for all posts from now on.)
Jar Jar, as you recall, is the obscene racial caricature who causes discomfort in us that prevents us from seeing them as fully human.
This is Hancock who wakes up hungover on a public bench. This is the Hancock who is a drunk hobo who tries to do good but screws up so egregiously that everyone despises him and objectivizes him (which is a cover for their fear of him). This is the Hancock who crashes into things and shoves criminal's heads up... bad places. This is the Hancock who is intensely miserable, and gives us a ton of great class imagery.
Luke (by the end of ROTJ) is the smooth, confident heir to a powerful legacy who lets others have romantic love while he shares a spiritual love, and goes out to fight for universal ideals.
This is Hancock flying away so Mary can live (and love Ray). This is Hancock spreading a global message of love and justice.
Of course, both Jar Jar and Luke filled the same plot role in their respective trilogies (protagonist, the innocent who begins the quest). The switch from one to the other isn't about the change in themselves but about the change in our perspective of them.
Hancock, the movie, was critically drubbed for "promising" a comedic movie, which it is in the first half, then transitioning to a serious drama in the second half (this transition starts with the fancy restaurant scene, and ends by the time Hancock is shot). The cinematic perspective changed from comic, to heroic. Fans were promised Jar Jar, and were confused when he turned into Luke Skywalker.
Hancock can be viewed as a underclass monster whose hideous strength is an afront to our sensibilities. When done so, he will act more and more like that (and he had been stuck in that cycle since the 1930's (there will be a whole post on the 1930's)). Hancock can also be viewed as an ideal of sacrifice, and love, and justice.
The whole movie is a lecture on the importance of performative efficacy. This is an anti-humanist concept that the world calls you something, you become that thing. Our bootstrap idealistic liberal culture is very uncomfortable with this concept, so films that shove it in our face front and center serve a very valuable function in reminding us of the power of social definition.
Our perspective changes on our lover, and we distrust them. So we fight with them and they earn that distrust and we believe we were right all along. It's a helpless cycle to feel caught in, but it's a cycle from the outside you must do everything to try to break. The trio of Hancock, Ray, and Mary try in their fumbling and broken ways and show that real progress can be made.
But first, we have to discuss how he was made such a lowly creature in the first place.
Wow, we got through this whole post without using profanity. Don't worry, that streak will end tomorrow.