The Akatsuki could still be the main antagonists. Even with Naruto having the power of the Speed Force, they would pose a significant threat. Their various unique abilities and their goal of collecting the tailed beasts would still be in conflict with Naruto's desire to protect the villages.
One interesting concept could be Naruto being able to access the Speed Force to quickly move between the Hidden Villages. This would give him an edge in battles and also in delivering important messages.
If Naruto were blessed by the speed force in a fanfic, it would completely change his fighting style. He could quickly close the gap between him and his foes, and his rasengan would be delivered in a blink of an eye. Also, his ability to gather information on the battlefield would be enhanced as he could zip around to different locations rapidly.
Well, in this fanfic, Naruto's use of the Speed Force could lead to some really interesting crossovers. Imagine him meeting characters from the DC Universe who are also associated with the Speed Force. He could learn new techniques from them or teach them some of his ninja skills. In terms of the Naruto world, his newfound speed could make him a more elusive target. He could use it to quickly gather intelligence across different villages without being detected, completely changing the power dynamics in the world of ninjas.
One possible fanfiction could involve Naruto being transported to the Young Justice universe and somehow getting connected to the Speed Force. Maybe he gains super - speed abilities and has to learn how to control them while also dealing with the threats in the Young Justice world. He could team up with the Young Justice characters, like Robin or Kid Flash, and use his ninja skills along with his new speed powers to take on villains.
His power level would skyrocket. The Speed Force gives him the ability to move at incredible speeds, which adds a whole new dimension to his combat capabilities. He can now dodge attacks with ease and also deliver rapid - fire strikes.
He would probably be extremely fast, able to move at speeds that would shock his opponents. His attacks would become more unpredictable as he could quickly close the gap between him and his enemies.
Well, he would be super fast, for sure. He could zip around the battlefield so quickly that his enemies wouldn't be able to keep up. He might be able to use his new speed to perform his jutsu even more effectively, like hitting multiple targets in an instant with a Rasengan.