He'd still range within the top 5 relatively speaking.
Massive reserves that improve over time. Even without Kurama he's top 5 in the series for chakra reserves.
- Hiraishin and all of its variants via Minato. Meaning both V1 and V2, Minato's over complicated technique AND S/T barriers provide a nearly impermeable defense.
- Sennin Modo training via Jiraiya once more, as there would still be the relation between Minato and Jiraiya which would be passed down to Naruto.
- The application of the Uzumaki's overpowered sealing techniques that Naruto could use in conjunction with his normal arsenal, to give him more versatility.
- Higher IQ and or better intellect. He was a "trickster" and academy failure because he wanted attention all the time from everyone, and that made him devoid of all academic responsibilities. With a genius father and an Uzumaki mother, he'd be at a far higher aptitude for intelligence as far as tat quota is concerned.
- Development of Fuuton techniques beyond just Fuuton: Rasenshuriken (which he would learn anyways). That, and he could develop 1-2 more elemental masteries, similar to how Kakashi knows Suiton, Doton AND Raiton.
- Continued use of the Kage Bunshin but with all of the above.
