Well, it depends on various factors. If it manages to blend the elements of Naruto and the concept of Zanpakuto in an interesting way, it could be great. However, without actually reading it, it's hard to say for sure.
Aizen Sosuke is also a strong contender. His intelligence and manipulation skills, along with his unique powers, make him formidable. However, it's subjective as different characters have their own strengths at different points in the story.
You could try looking on popular fanfic websites like Fanfiction.net or Archive of Our Own. They usually have a wide variety of fanfics, so there's a chance you'll find it there.
There are some really interesting ones out there. You can start by looking on fan - fiction websites like FanFiction.net or Archive of Our Own. Just search for the relevant tags like 'Naruto', 'Bleach', 'Kyuubi', and 'Zanpakuto'. Some stories might combine the elements in unique ways, such as a character from Naruto getting a Zanpakuto - like weapon with the power of the Kyuubi.
First, get to know the lore of both Naruto and Bleach really well. Understand the nature of the Kyuubi's power in Naruto and how Zanpakuto work in Bleach. Then, come up with an interesting concept that combines these elements. For example, what if a Naruto character was given a Zanpakuto that was powered by the Kyuubi? Plan your story structure, create engaging characters, and start writing.
It's hard to say for sure. Naruto in his Sage of Six Paths mode is extremely powerful, with access to a vast amount of chakra and the ability to create and manipulate Truth - Seeking Balls. But Ichigo, when he reaches his final form, can also be a force to be reckoned with, having the combined powers of his Hollow, Quincy, Soul Reaper, and Fullbringer heritage.
At first, Naruto would be clumsy with it. He has no prior experience with Zanpakuto. But his determination would drive him to practice. He'd study how to hold it properly, how to swing it effectively. Maybe he'd even talk to it like he does with his friends, trying to understand its spirit if it has one.
Perhaps they are a gift from a mysterious and powerful being who sees Naruto's potential. This being could be observing the Naruto - verse from afar and decides that Naruto is the perfect candidate to wield dual zanpakuto. The being may have their own reasons, like wanting to see how Naruto will use the powers of two zanpakuto to change the balance in his world.
Naruto could have a Zanpakuto with the ability to create illusions of hope. Given his character, it would make sense for his Zanpakuto to have an ability that gives his opponents a vision of a better future if they stop fighting. This would be a non - violent way of ending battles, which aligns with Naruto's ideology. Another possible ability could be to transform his chakra into a tangible form that can be used to either heal or boost the strength of his allies. It would be like his chakra is being channeled through the Zanpakuto in a more controlled and versatile way.