The OP powers of Naruto and Sasuke will be taken away by Madara.

[-ahhimane-]

That Madara, hungry for more power, will take away Naruto's and Sasuke's powers at some point in the manga.
Why I say this?
1) About Naruto :
Naruto already showed in the last chapter what he is capable of doing with that power. He regenerated Kakashi's freaking left eye. I think that was the CLEAR hint from Kishi saying "I'll be taking these powers back or there won't be any interesting Naruto vs Sasuke battle".
2) About Sasuke :
As we know, sasuke is Indra's reincarnation, Indra had powers up to Perfect Susano'o that is EMS, Whereas the eye that Sasuke got from Hagoromo is most probably Juubi's eye. Sasuke is shown not using Susano'o when he could have used it to stop Madara from approaching Kakashi quickly. Also his right eye seems to be only up to 3-tomoes. If he is capable of using only powers from his left eye then he is surely at a huge disadvantage once Madara finds how exactly Sasuke's left eye powers works.

Snatching away their powers will really drag the story down to earth where Shinobis live. Lol
I want that to happen.

 

[Kαmi]

Yeah I never thought these power-ups would be permanent. It's just too much to have them be so strong like this for the rest of their lives. It's something I don't mind though, especially if it's due to Madara's hunger for power

 

[Zealous Sparks]

Madara already stated that he was interested in trying to take Sasuke's left eye (because it was compatible with him). So this is a possible idea. Though for Naruto, how would Madara be able to take his power away?
He already took Yang-Kurama from Naruto so I don't think Naruto will lose the bijuu again.

 

[Alfred Pennyworth]

I hope so. I dun like hax protagonists

 

[-ahhimane-]

Madara already stated that he was interested in trying to take Sasuke's left eye (because it was compatible with him). So this is a possible idea. Though for Naruto, how would Madara be able to take his power away?
He already took Yang-Kurama from Naruto so I don't think Naruto will lose the bijuu again.

It's still unclear whether Naruto's power up is because of all the bijuus' chakra or sage gave it to him without the bijuus' connection to the power up. But if this is going to happen then Madara's both rinnegan powers will do the job.

 

[Zealous Sparks]

It's still unclear whether Naruto's power up is because of all the bijuus' chakra or sage gave it to him without the bijuus' connection to the power up. But if this is going to happen then Madara's both rinnegan powers will do the job.

Maybe Madara will get a power somewhat akin to how Aang took away the Firelord's bending in Avatar.