I don't understand too. People here are rushing things in the manga. Nobody is qualify for the Hokage position meaning Naruto and Sasuke. Shikamaru is still too young and a Chunin, Kakashi don't wanna do it so....... why do she need to die espically the kages.
I kind of agree but disagree as well for a few reasons:
Tsunade dying would have made the war seem more real as major characters were dying. While I am glad she is alive it is bitter sweet. She is the most powerful medical ninja in the Narutoverse yes, but Sakura should have taken this mantle as is in the reoccurring theme of the next Gen passing the previous.
Naruto surpassed Jirayah
Sasuke surpassed Orochimaru
Sakura should have surpassed Tsunade as well.
No one to hold the position of Kage. Last I checked Kakashi was next in li r to be Hokage after the death of Danzo. Even Jirayah and Tsunade agreed in this.
And also, wasn't Hiruzen around Naruto's age when Hashirama and Tobirama began his Kage training?