One possibility is the power to create infinite clones that also have infinite speed. This would be an overwhelming force against any enemy. He could also have the ability to manipulate time in a limited way while using his infinite speed. For example, he could slow down time for his opponents while he moves at normal speed within his infinite - speed state, giving him a huge advantage in battles.
He could absorb the Sharingan ability. Imagine Naruto with the power to copy jutsus just like a Uchiha. Another interesting one would be the Byakugan. He could gain enhanced vision and be able to see the chakra points even more clearly. Or perhaps the ability to control sand like Gaara. That would be really cool.
There's a fanfic where Naruto's super speed and strength are combined in an amazing way. He races up a huge cliff in seconds with his speed and then, at the top, he uses his strength to pull a massive boulder and hurl it at the enemy base. It was such an epic moment as the boulder crashed into the base, causing chaos among the enemy forces.
One cool element could be ice. An ice - added Rasengan would be amazing. It could freeze opponents on contact or create icy terrain around the battlefield, giving Naruto an advantage in controlling the fight. Another great option is the lightning element. A lightning - Rasengan would look super cool and have high - speed and powerful electrical discharges that could stun enemies.
The coolest aspect would be his new elemental powers. Kakuzu had different hearts for different elements. Naruto could combine these with his own Rasengan. Imagine a Rasengan infused with multiple elements from Kakuzu's hearts. It would be an extremely powerful and unique attack.
He could develop the ability to combine his chakra with Superman's powers. For example, he might be able to use his Rasengan while flying at super - speed. Or he could infuse his chakra into his heat vision to make it even more powerful.
Some Naruto Infinite Stratos fanfics focus on the crossovers in battles. Picture Naruto's Rasengan being used in an IS battle against an enemy that has both the advanced weaponry of Infinite Stratos and some sort of ninja - like abilities. There are also fanfics that explore how the different cultures in Naruto, such as the Hidden Villages, would interact with the international setting of Infinite Stratos.
Well, it can completely change the power balance. With infinite speed, Naruto can outmaneuver any opponent easily. He could rescue his friends in an instant, prevent disasters before they even start. For example, he might be able to stop Pain's attacks on Konoha before anyone gets hurt. This would make the story more about Naruto's quick decision - making on how to use this power rather than the struggle to gain power.
He could have the ability to fly by using sonic waves to propel himself. Just like how some characters in other stories use sound to levitate. Another cool ability would be to create sonic shields. These shields could protect him from attacks by vibrating at a high frequency and deflecting incoming projectiles.
He could have the Sharingan's ability to copy and predict moves. Also, the Byakugan's near - 360 - degree vision would be really cool. And if he had the Rinnegan, he could use all kinds of powerful jutsu like the Deva Path's gravity manipulation.
He could develop the ability to combine his chakra with his Spider - Man powers. For example, he could infuse his webs with chakra to make them stronger or even give them different properties like being able to cut through objects. Another new ability could be using his shadow clones in combination with his Spider - Man agility. He could send clones to different locations while swinging around with his webs, creating a more complex battle strategy.