Han Solo had a heart of gold under his vest of black. That being said, he had a quick trigger-finger to answer anyone who questioned his character – but as time wore on, and as medals weighed increasingly heavy around his neck, that happened less and less. He preferred conflict to questions, recklessness to forethought, but when he started something, he finished it – and when he kissed the princess, it was a promise he meant to keep.
(He loved her every second of her absence, loved her every heartbeat spent on the boy who refused to come home.)
Finn emblazons himself with titles like Resistance, like friend, but the brands beneath his skin go deeper: numbers where a name should be, instincts where desire should be, an empty cavern where he thinks some sort of expectation ought to live. He wasn't trained to expect; he was programmed to execute.
(The marrow of his bones knows what it is to kill, but his hand freezes on the trigger every time he tries to silence this slow sickness they've built into his veins, this automatic acquiesce to what someone else wants him to be.)
Han Solo was always a good man, albeit stained with questionable deeds, careful to wash his hands clean before he offered them to a princess for the rest of his life.
Finn is a villain for whom redemption is like a new suit of armor – one that fits too snugly, makes him itch and squirm and sweat, his First Order uniform still trapped beneath it, the helmet bright with blood-stripes.