Aside from the two of you looking to generate several pages of debate team practice, Han isn’t a terribly deep character because Lucas isn’t a deep thinker or writer. I don’t think he had any idea what to do with him after Star Wars. He’s not even part of his first sequel (Splinter). I’ve never read the second writer’s sequel, so I don’t know what direction Brackett was taking him in, if any.
IIRC, Harrison wasn’t under contract for a sequel at the point in time Splinter of The Mind’s Eye was being considered as the economical “plan b” approach for the next film.