Oh my god. Why on earth are you so aggressive, hahaCongratulations, you have an opinion.
I mean if you're going to "muh opinion" in here, the least you could do is explain why you're fascinated by characters with regressive character development.
Before I say anything I want to point out that forcing someone to enforce their opinion is probably not a good idea mate. Just calm down, have a cup of tea and understand that some people, just dont see things the way you do.
Han Solo and Princess Leia were a bickering couple even through the original trilogy. We are shown how they love each other, yet also how both have opposite personalities. After Kylo went evil, it makes sense for me for them to drift away, with Han Solo, the scroundel that he is, choosing to be a smuggler again. I've seen relationships like that before, hell, I've been in a volatile relationship like that once.
With Luke, he became a Jedi, but then again he is also the only remaining Jedi Knight in the entire galaxy. He was also impetuous, like his father, and barring the Force providing anti-depressants him deciding to be a hermit after absolutely fucking up does makes sense.