Battle,
Finn didn't defect, he deserted. That's a difference. He didn't join the Resistance, he just ran away from the First Order.
Mind of Shadow,
I totally get what you and Hype are saying and I've said similar things. Finn got whooped by the nameless Stormtrooper who some fans started calling T8TR during the scene where the First Order and Resistance were fighting and Rey was captured.
Finn was a reluctant hero. Even the Entertainment Weekly article calls him that. Now in the past some have argued that that was a good thing, that Han was also reluctant. Which is true, but Han eventually turned around and grew from being selfish to being part of something bigger than himself. It is likely that Finn will have a similar arc though it appears like they are stretching that out, and that's to Finn's detriment.
Finn didn't rescue Rey. The film made sure to show that Rey rescued herself. Finn did help out, though he needed help taking down Phasma-though he did identify her as being someone to take down-and Finn played a role during the destruction of Starkiller Base though after admitting he was a janitor and didn't known much about the workings of the base. He didn't get any clear wins like Luke or Han did in Episode IV and he didn't even get an accidental win like Anakin did in Episode I.
They couldn't let Finn have a clean win. And Luke was naive and idealistic but no where near as awkward as Finn or even in the friend zone like Finn. Leia did kiss him-twice I believe-though once was to spite Han. That's more than the chaste forehead kiss the comatose Finn got after he risked his life to 'save' Rey. That was like her kissing a favorite pet. The feminist and white agenda in effect in the Force Awakens made sure that Finn would not save Rey and that her knocking his hand away or escaping from Kylo Ren on her own were touted as girl power, which they were, but noticeably at the expense of a black male character.
Finn did fight Ren, for Rey. If Rey's life wouldn't have been in danger Finn wouldn't have been around. And to his credit, he did last a little while against Ren. Though that might have been because Ren was injured or toying with Finn.
What I'm guessing is that the new character Rose will be a love interest or something close to that for Finn to keep his black paws off pristine lily white Rey.
I think some black folks are blinded by the fact that a black face is in this new Star Wars triumvirate without considering what kind of character Finn is portraying. Simply having representation is not enough. If this was the '60s, fine, but it's the 21st century, and the idea that we should accept, ignore, or make excuses for problematic portrayals of black characters, even in the franchises we love (and I do love Star Wars) is worrisome. But I think too many of us are just happy to see somebody black on screen and we don't expect anything more than that.
To me, Finn was a colossal fail, even worse than Jar Jar Binks. At least with Binks, he was a CGI creation and he was countered by Samuel L. Jackson's Mace Windu. So far there isn't any other black character in this new Star Wars. There was one black female in Force Awakens, Korr Sella, who had no dialogue before the planet she was on was destroyed. In the canon she was Leia's assistant. In the novels set between Episodes VI and VII there is at least one other important black character, Rae Sloane, but so far she has not debuted in live-action.
Also, the b.s. future or end result of the Han and Leia relationship foisted on us by The Force Awakens erases, but can't completely, the tons of now non-canon material that did explore their relationship. Their marriage was an important part of the canon before the Disney buy out. Also, I'm guessing that the canon Marvel comics is building or will build on that relationship. It is very doubtful we will see anything similar to Finn with Rose (and definitely not Rey). Even with TFA we saw glimpses that Han and Leia still cared for each other even if they couldn't live together anymore.
http://starwars.wikia.com/wiki/Korr_Sellahttp://starwars.wikia.com/wiki/Rae_Sloane