Yeah, I totally understand that. Long storylines are definitely prone to contradictions and retcons, ...but I don't really see this applies to any of the examples I brought up in my post? My problem isn't with authors retconning or forgetting things. The closest thing is in Avatar example, but even the Ozai conflict was given plot attention only a few episodes before the finale.

In Mushoku Tensei's case, it's not simply about the author contradicting a plot point they brought up earlier in the story - it's about them never addressing the pedophilia that they themselves gave the character. I feel like that's less about long-term planning and more about them either just not caring to address pedophilia or not believing pedophilia to be that bad or a negative character trait.