That's sort of what I was getting at. I don't see him as a completely selfish person who turned into a completely selfless person by the end of RotJ. I see him as a basically selfish person who's willing to make a few exceptions for people that he's most fond of. At the start of ANH, only Chewie and maybe Lando were people whom he would risk his life for. By the end of RotJ, the list had grown to include Leah and Luke.
They can simply portray him the same way in the new films. In fact, he may even start out as someone who really does care only about himself, until he rescues Chewbacca and meets Lando. They can also introduce some other characters (especially Woody Harrelson's, if he's, indeed, his mentor) that he might make exceptions for and risk his life for, just as long as they're out of the picture by the end, so that his character segues nicely into the drifter with only one or two friends that Luke and Obi-Wan meet in the cantina.
