You ever think at some point Sasuke thought Kakashi was involved in the massacare in Part 1? I started reading the manga over again and I thought this was a nice little hint. (Part 1 was some good shit)
That would be cool, however, in his latest interview, Kishimoto said that he wasn't planning ahead much at that point. For Sasuke, his backstory was just "he had a brother who did something bad".
Edit: just in case,
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. And here's the exact quote:
At the time he was just making these things up for the excitement and suspense, but didn’t pick up on what to do with some of these threads long-term until later. Basically he was making it up as he went. Even with Sasuke’s backstory, at the time of the Wave Arc, all that had been thought out was that Sasuke had an elder brother who had done something bad, and that was it. Kishimoto admits the planning was very hazy at this point.
So the massacre wasn't planned at that point, apparently.