- why bother making Kakashi walking up to his dad to talk about his past life at all? Kishimoto could've easily just done it Asuma-style or even Jiraiya-style. Why the flashback?
- in terms of significance, Chouji's dad isn't that important but to serve as a 'pass the generational leadership' plot device. Very few parents have been acknowledged w/ 'screen-time' so offing Chouji's dad is to show how severe the Konoha attack is, how personal the fight is.
- killing isn't necessary for the next generation to step up in a leadership role. Hell, the Third Hokage stepped aside to let the Fourth lead until he died
- I don't doubt that Kakashi has a higher than likely chance of dying near the end of the manga but not just yet. He's still got some things left unfulfilled to accomplish and he doesn't seem like the kind of guy who'll turn over and die in the face of a stronger enemy.
- You'll have to note that another constant theme in the anime is deception. This is displayed in the notion of all Bushin clones, Shikamaru's razor-sharp tactical mind, Naruto's fox-like mischievious nature, Orochimaru seemingly coming back to life time & again*, Itachi's manipulation of Sasuke, etc.
*don't forget while Sasuke destroyed his Orochimaru possession, Orochi's assistant Kabuto still has his