Reason why I created it was simply because it post-time jump couldn't be discussed in the anime due to spoilers. If you really want to to be technical you could argue that since shinigami are etheral beings and the naruto ninjas are coporeal then it would be impossible for them to fight. But considering that the whole ghost thing has been thrown out after the first few episodes you could use Chakra/Raitsu as the common factor by which to judge this imaginary fight.
Here's another interesting proposed fight, who would win the third hokage vs. the old man, whose head of the thirteen squads. My vote is for the hokage simply because he can summon the pimped out monkey king who transforms into a diamond pole. That would put him on even fighting terms against the old guys super fire soul slayer.