First, I have a question for all the good debaters of NarutoBase who are debating here.
Is there any rule that states that one person cannot be a vessel for two different transmigrants?
Ok, this was just a question to draw your attention on some logical devices - that is sometimes, establishing proper rules can avoid unnecessary discussion.
Now, on topic, I am 100% that Naruto may represent the same will that Hagoromo represented, but Naruto is not Hagoromo's reincarnation. I even believe that though Naruto is said to be the reincarnation of Ashura, Naruto is much more than Ashura's reincarnation. A blatant evidence is the fact that even hagoromo received a prophecy of Naruto's birth and actions.
See, there is a god in the Narutoverse who once chose Hagoromo to do a part of a job, and now, the same god has chosen Naruto to finish the job.