I'm always surprised when a 'supreme' Naruto or Sasuke fic manages to write a good fight that isn't just a list of new, made-up jutsu. The best ones I've read, like some of the older stuff on FanFiction.net, actually slow down and make you feel the exhaustion. They remember that Naruto's a brawler who gets back up, and Sasuke is precise and vicious. A fight isn't strong because someone shouts 'Rasenshuriken 2.0'—it's strong when you're wincing because Sasuke just used a genjutsu to make Naruto think he's stabbed Sakura, and Naruto's rage-breakout feels earned, not just a power-up. The emotional stakes have to be there, otherwise it's just special effects.
A lot of these fics get lost in the scale, you know? They have them destroying three moons and rewriting reality, but it feels weightless. I prefer the ones where, even with god-like power, the core conflict stays personal. Like a story where Sasuke, after everything, still tries to end it with a simple Chidori, because that's what he knows, and Naruto meets it with a Rasengan because that's their language. That simplicity amidst cosmic power says more about their bond than any universe-shattering collision.