I would never say he can easily* kill or defeat the 5 kages, they would give him a run for his money. however, gaara would never do that to naruto so in reality itd just be 4 kages vs naruto. The old midget dude is almost done, physically, so hed be down 1st. Mizu would get crushed 2nd, Knowing the reikage, hed sit back and wait to see how it went before he engaged, and tsunade wouldnt even try to graze him, if she did, Bijuu = DEAD tsunade. Shes strong and all, but WAY to slow for naruto, as well as mizu and gaara.(i think the old man too,) Reikage is even a little slower then him.
SM for Mizu, Old dude, and gaara (if he fought). KM for Reikage
and for tsunade? all he has to do is breathe on her.