His physical abilities would likely improve a great deal. Black Widow is a master of martial arts, so Naruto could become even more formidable in close - quarter combat. His agility and strength could be enhanced beyond what he achieved in the ninja world just through her training methods.
In this fanfiction, Naruto's chakra control could take on a new dimension. Black Widow might not understand chakra exactly, but she could teach him discipline in using his energy. He could learn to conserve his chakra better and use it more efficiently, perhaps even developing new techniques that combine his ninja skills with the strategic thinking he learned from Black Widow. For example, he could use his shadow clones to create distractions while he uses his chakra - enhanced strength to take out opponents in a more stealthy manner.
Naruto would likely develop his chakra control better. The toads could teach him unique ways to manage his chakra, like using it in harmony with the natural energy around him. This would make his Rasengan and other jutsu more powerful.
His chakra control would likely be extraordinary. Kyuubi is a huge source of chakra, so Naruto would have had early exposure to vast amounts of it. This could lead to him being able to perform more advanced jutsu at a younger age.
In this fanfiction, Black Widow could introduce Naruto to a world of high - tech gadgets and espionage. Naruto, being used to chakra - based techniques, would have to adapt. He might use his shadow clones in new and creative ways for spying or infiltration. Also, Black Widow could help him understand the importance of keeping his emotions in check during dangerous missions, which is something Naruto has always struggled with.
Naruto's development would be a very interesting mix. In Kumo, he'd be exposed to different types of chakra natures and fighting styles. His Rasengan, for instance, could be modified with Kumo's lightning chakra to create a more powerful and unique attack. Minato's influence would ensure that Naruto has a solid foundation in space - time ninjutsu. Also, being in Kumo, Naruto might learn to control his Nine - Tails chakra in a different way, maybe with the help of Kumo's unique methods of chakra control. This would make him an even more formidable ninja compared to his original development in Konoha.
His character might be more hardened. Growing up with Yahiko, he'd be exposed to the harsher side of the ninja world earlier. So he'd be less likely to trust blindly.
Naruto would be more disciplined. Gai's strict training regime would make him more focused on his goals.
Naruto's character would likely be more distrustful of traditional ninja institutions. Since he's raised by a rogue, he might see the established ninja villages as corrupt or overly restrictive. He could be more rebellious and less likely to follow orders blindly.
Naruto might become more sensitive and perceptive. Since kunoichi often have a different way of looking at things compared to male ninjas, Naruto could pick up on those traits.
Naruto's view of family would be different if raised by Pakura. Since Pakura could be seen as a surrogate mother figure, he'd have a different understanding of maternal love. This would affect his relationships with others, especially female characters. He might be more respectful towards women from the start. His growth as a ninja would be more centered around Suna's way of life. For example, he'd be more involved in protecting Suna's trade routes and resources, which would shape his ninja skills and values in a way that's distinct from his Konoha - raised self.
Naruto would probably be more in touch with nature. Since slugs are associated with earth and natural elements, he might have a calmer and more patient side to him.