Sasuke is a combination of kurapika background story(revenge, the last of it's kind, and eye power) and killua all about family( and killua assassin move).
Rukawa popularity and indifferent attitude (slam dunk).
And "save" tetsuo from Akira.
Kishi is not a creative mangaka.
The only good thing he could write is drama. More precisely soap opera drama.
Those are details of inspirations, in the end we can find such things in most of the works around the world. There are many things to take into consideration when developing a story, I am gonna give Kishi the benefit of doubt in some terms, he did build after all a great world and all that, the problem he's lacking at is characterization along with character development and mostly he suffers in the realistic development department... When people say it's just a world and all that, it's fantasy, yes I agree with them, it's fantasy but even that world has established some moral codes and for the moral codes that Kishi himself built in his story the bad part is that he doesn't live up to them. And he has a biiiiiig problem with accountability. I get it, it might be part of the charm of the story but you can only pull this for so long... as in, at a point, like it was in his story, it starts degrading the story.
I've seen many many many problems with his manga from the very beginning, however, I looked past them because this was first and foremost a manga about bonds and so many happen in rl too. It was magical up to a point, the way he portrayed these bonds and everything else... up until he really started to screw-up with over emphasis on certain things which up to a point work, as I said, but then they start degrading the story.