I think them not humanizing the stormtroopers after having one as one of the main characters in a trilogy is one of the biggest missed opportunity of the ST for me. Especially if they decide to humanize them in ancillary materials like they did with the clone army in TCW. TLJ's junior novelization mentioned Finn had one regret: not convincing other troopers to do the same. There is also a comparison with the Jedi order and the clone army who took children from their families and raised them as warriors which I don't agree with since the Jedi gives parents a choice while they didn't. Though, to be fair this was from Hux's POV, unreliable narrator and all that. I was a little disappointed it took Finn two whole movies to commit to fighting with the Resistance but I liked the relationships he built with Rey, Finn and Rose the most. His arc in TLJ was to stop selfishly caring only about Rey and to think about the bigger picture while Rose had to stop hero worshiping Finn. I didn't like that he didn't have a single interaction with Rey aside from the hug after the focus on them both in TFA, I feel like their relationship didn't evolve beyond the fact that now he care about more people hence why I think there will be no romance between them, plus there is Rose's kiss to think about.