I've always held the belief that since its first appearance, that Naruto's Bijuu Mode isn't exactly what we think it is.
As we know, Naruto's Bijuu Mode takes on the form of Kurama. But however, it's not a full flesh replica like Bee's Gyuuki form. Instead it's a huge chakra shroud in the form of Kurama.
I believe that Naruto's Bijuu mode is nothing less than a "V2" of his RM cloak. Think about it, Bijuu mode also changes his appearance, and changes his body marking as well as giving him the Minato-like cloak. We know that Ver.2's characteristic is that it allows the Jinchuurikis to take on a closer form of their respective Bijuus. Moreover, it also takes the form of a denser chakra cloak.
Now, what if Naruto's Bijuu mode is indeed a "V2" of his initial chakra cloak?? the hint is that Bijuu mode take the form of a chakra shroud like V2, brings Naruto to a closer form of Kurama,and lastly, Kurama himself stating that their link is not perfect yet.
My guess is that through further training to perfect their link, Naruto's Bijuu Mode will eventually take on the full flesh form of Kurama.
I think Gyuuki will eventually realize that Naruto's Bijuu mode is very similar to V2. Not only that, he'll likely realize that Naruto can compress said form into a human-sized form. We know that V2 is essentially a compressed, human-sized form of the Bijuus themselves. The human-sized form of Naruto's Bijuu mode will be just the cape and new markings without the chakra shroud of Kurama.
I'll agree that this isn't the final form of his cloak, but I'm thinking that Naruto will never turn into a full-flesh Kurama. He will be something more unique than the other tailed beast and jinchuriki. Especially since that he now has the chakra and names of 7 of the 9 tailed beast. I'm thinking he will resemble the SoSP more. Also as the main character, he has an obligation to stand out from the others.