When Naruto gets older he is going to be like old Hiruzen, he couldn't disburse his clones. This will hinder him in combat, if Naruto where to never learn how to use Rasengan with out Shadow clones then it would be a problem.
Hiruzen couldn't use Clones against Oro and the 2 Hokages because if his old age it would use up his chakra. He used it in the end and barely sealed the Kages and Oro's arms.
My point is when Naruto gets older he is going to be useless. All his attacks revolve around using Shadow Clones. I doubt at old age he will be capable of using even Sage Mode. The only way Naruto could use Sage Mode is only if he makes clones before the fight and summons them with a scroll. There goes the clone problem again..
My point is that Naruto needs a new variety of Jutsu, or Kishi needs to show us a one hand rasengan without BM.
Are you serious right now??
The only reason Naruto is bad with chakra control and why he needs to use clones to make a Rasengan is because of Naruto holding back Kurama's chakra ALL the time.
Now that they are friends Naruto doesn't have to worry about that problem anymore so he can achieve a lot more especially by time he is 18/20. The way that he can rain with his clones and the sheer potential of jutsus and power that he has is greater than any Kage before him. I see by time he is his Dads age he will have become the greatest Hokage the Village has seen and not all based on Kurama's power.
I especially believe that by the time that he is Hiruzen's age he will become the new God of Shinobi and will be a much bigger legend than his dad or any Kage ever was. The way I see it if he progresses the way he has over the past years he will stronger than any other and no young ninja will be able to be able to achieve his power again unless someone becomes the Jinchuriki of the Juubi.
Hell if he wants to at 60 Naruto would be able to send off 5000 clones all who can transform into way more powerful BM, KM, SM, and even Base Mode into a battle field and sit in his office eating some Ramen Noodles..