If SM could destroy all the forests and beat kurama once, then why isn't it > five kage. Just think of it:
Madara's wood tech could beat the five kage, and naruto countered it easily. So Naruto > Five Kage
All of us believe taht five kage > BM Naruto
It was dificult for naruto to deal with even only one of them, raikage.
So Five Kage > BM
SM > Five Kage > BM