kishi took away rsm because he realized it didnt make sense

[Ultimateone]

as many have already said, naruto did not lose RSM. it was changed because it haddened been introduced in the anime yet and would have spoiled it for many. think about it for a second. why would naruto's cloak look anything like that if he was to get a full kurama. it would have looked like an evolution of his BM but it looked like a different design to his kcm. so either in the movie he just didn't use his full power, or kishi didn't want to spoil it. also in the movie, there is a scene where toneri takes a huge portion of naruto's chakra. only after that does naruto enter a chakra cloaked form.

but to answer your question, it makes sense that naruto's version was stronger. first you have to realize that naruto's power only partialy comes from the bijuu chakra. the sage literally gifted him part of his power. making naruto's own senjutsu evolve while perfectly mixing with the bijuu chakra. also, the bijuu are chakra monsters. they are huge masses of chakra, not the same as everybody else in the naruto world. taking a piece of their chakra is like taking a piece of them. therefore it makes sense that naruto was able to talk to them. your problem is almost like saying why did sasuke get a better rennigan. sure he didn't have limbo's, which he may get later as he matures. but he could use chibaku tensie without using the black gravity sphere. he could insta trap bijuu in genjutsu. he also had that swapping tech. but back to naruto for a sec. we have been told many times that a perfect jin is stronger than someone who just takes the power. even still we need to remember that even after naruto had used up all the bijuu chakra, he still could use his RSM. which basically means that it wasn't the bijuu chakra that made him that way.

 

[chaos control]

madara had 3 rinnegans, all the bijuu, senju dna, uchiha dna, and some of kaguyas power there is no reason why naruto shouldve looked like he could win 1v1. and no naruto beat the shit out of kaguya now that i think about it she only got one hit off one him and it didnt even hurt the only reason he couldnt win alone was because he didnt have both seals himself.

Kaguya actually wrecked both Naruto and Sasuke. The only reason she lost is because Kishi made her really stupid. When she paralyzed Naruto and Sasuke and then started draining their chakara while crying, that was a victory chance right there. She could have just hit them with ash bone while they were paralyzed instead of going for the chakara and then gg Naruto and Sasuke.

When Kaguya changed it to the ice dimension she actually froze Naruto and Sasuke in a block of ice (and got out of it herself). Sasuke was the one (not Naruto) that used amaterasu to melt the ice. That means that if it was just Naruto alone, then Naruto would have been frozen for a longer time at which point Kaguya could use ash bone and then gg Naruto.

In the gravity dimension Kaguya was actually about to kill both Naruto and Sasuke at the same time. Obito had to come in and save them at the cost of his own life. That is another point for Kaguya.

Had Kaguya actually thrown that massive truth seeking ball instead of just making it hover, the explosion would have easily killed both Naruto and Sasuke. This just goes back to Kishi making Kaguya stupid.

Not to mention the fact that Kaguya didn't just put Naruto individually under the infinite tsukuyomi with her rinne sharingan. Naruto doesn't have rinnegan or perfect susanoo, so he wouldn't be able to avoid or counter it. Once again, Kaguya being stupid.

Yes Naruto got some hits in on Kaguya, but it is clear that if it was 1 on 1 then he would have lost, Sasuke would have lost 1 on 1, Obito would have lost (and needless to say Kakashi and Sakura would have lost).

Kaguya>> Naruto

Also, Naruto didn't lose rsm. Naruto was able to fly in the last (without wings, a summon or a susanoo). Now we have seen 2 methods of flight in the series that don't involve wings, a summon or a doujutsu. Those methods are:

Six paths flight
Earth style light weight flight (the version Onoki uses).

Now why on earth would Naruto all of a sudden have some random earth style jutsu that only tuschikages have been known to use? It is much more sensible that the method Naruto used to fly was six paths flight. Six paths flight requires six paths chakara (4th databook). Therefore Naruto still has Hagoromo's chakara and therefore still has Rikudou Sage mode.