Handling the Rinnegan would be cake. Moreover, it's an absolute joke, this assertion; Naruto is the effective leader of the free world, a larger than life symbol of peace and stability, and the guardian of good. The last line of defense against real evil. The world would crumble into its old state without its guide. The Bijū would roam uncontrollably and up for grabs, which could cause another global war. Literally *everything* rides on Naruto.
Sasuke might as well already be dead. Took him, what, 10 years jerking off in the woods and plot-device of wandering a castle aimlessly to figure out a threat was looming? We'd be short a one-armed peasant if that clown died. Naruto could either take his Rinnegan and master it in no time with his chakra expertise and Rikudō prowess, or toss it to the homie Kakashi as the original plan was.
The known universe dies without Naruto. Don't even compare that servant to a King