So, in the latest chapter of the manga, it was shown that Sage Mode will play a vital point in the battle with Obito. We have also speculated on what Sage Mode mixed with Bijuu Mode would look like. Well I believe this all has to do with Naruto being the reincarnation of the Sage.
I believe that when Naruto is in Sage Mode and activates Bijuu Mode, That his Sage Chakra will interact with the collective chakra of all the Bijuu. I believe he will reach a state similar to Obito's; however, I don't think this transformation will take place until Minato is destroyed and Naruto receives the "Dark Kurama". It is in this instance of activation that I believe Naruto will have his meeting with the Sage of Six Paths. I believe the sage will appear to Naruto because he will have become his successor not by forcibly extracting Bijuu from jinchuuriki but by truly inheriting his will and the Bijuu's trust.
In conclusion, I believe that Sage Mode mixed with Bijuu Mode will be the catalyst to Naruto's next power-up as the true successor of Sage. Thus, giving him a completed SO6P Mode, unlike Obito's who's is incomplete (Notice the Horn inconsistencies. May just be because Juubi wasn't in final form though). It would make sense for Sage Mode to be the catalyst for Naruto to meet the Sage of the Six Path's though, just a thought.
I believe that when Naruto is in Sage Mode and activates Bijuu Mode, That his Sage Chakra will interact with the collective chakra of all the Bijuu. I believe he will reach a state similar to Obito's; however, I don't think this transformation will take place until Minato is destroyed and Naruto receives the "Dark Kurama". It is in this instance of activation that I believe Naruto will have his meeting with the Sage of Six Paths. I believe the sage will appear to Naruto because he will have become his successor not by forcibly extracting Bijuu from jinchuuriki but by truly inheriting his will and the Bijuu's trust.
In conclusion, I believe that Sage Mode mixed with Bijuu Mode will be the catalyst to Naruto's next power-up as the true successor of Sage. Thus, giving him a completed SO6P Mode, unlike Obito's who's is incomplete (Notice the Horn inconsistencies. May just be because Juubi wasn't in final form though). It would make sense for Sage Mode to be the catalyst for Naruto to meet the Sage of the Six Path's though, just a thought.