Kurama is altering Naruto's chakra control from his birth, and he mastered rasengan in days although Tsunade said it was impossible, she said that was prodigious although he was handicapped.
With an unaltered chakra control, Naruto would be a prodigious prodigy never seen before, he would solo Sasuke pretty easily at any time of the story.
Naruto has always been alone with nobody to teach him techniques except his teachers, with his parents teaching him clan techniques, he would be able to solo anybody except juubi jins.
And don' t forget that Naruto would still be the child of the prophecy and host the 9 beasts (RSM) at some point.
Naruto would definitely be way stronger than what he is now.
Wrong, he would master sage mode faster, Kurama is altering Naruto's chakra control and didn't want the elder toad to help Naruto.
He would still have KCM/BM/BSM as he would still be the child of the prophecy.