I see Han as a criminal. At no time was he ever depicted as being anything other than that. He wasn't going to college on the side to become a paralegal. He wasn't hoping to one day become a writer. He was a 30-40 year old man who smuggled drugs and other contraband. I can totally see his character arc going in the same direction as, say, Jax on Sons of Anarchy, especially if the thing with Leia didn't work out. By the time he is 70 (where he kind of would be if Ep VII is written to the actual actor's ages) Han might be a glitterstim kingpin or working for the much more entrepreneurial and driven Lando. Not because he hasn't matured or grown, but just because that is the life he knows.