I think there's just different dynamics, which is why the story is different. In Naruto/Sasuke's relationship, Sasuke played everything, and vice versa.
Sasuke was:
* Naruto's supposed best friend AND rival
* Naruto's equal
* Naruto's motivation
* Naruto's work partner
In Boruto/Mitsuki's case, Boruto is just Mitsuki's friend. I don't know if they are rivals, because this guy exists:
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And Boruto's work partner is Sarada
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Boruto knows he has a lot of things to do before he is ready to become Sarada's support one day. He's striving towards being her partner.
So it's not "defined" as Naruto and Sasuke who were labled as one thing and one thing only. They all have multiple roles to play, some get their roles later down when they become adults, like Boruto said.
But I don't think Mitsuki nor Boruto take each other that seriously like these two:
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Thoughts?