don't worry, re-reading it after the shock of what was about to happen reveals the words:
"It may expire but its definitely not something useless."
So can the starving for relevancy Kakashi fans please calm down and take it Obito's words of truth? I'll admit even as a fan growing up watching...
just like zetsu said during Sasuke and Itachi's fight, a weapon is only as powerful as its wielder.
as far as cutting power though, Futon is superior and I'm not even going to argue, its just fact
1) Madara took back his other eye
2) Obito is apparently under his control
3) Sakura was penetrated by Madara
4) Sasuke doesn't care, Sakura was sad he didn't care
5) Raining boulders, no biggie to destroy
6) Madara reveals he has Kaguya's forehead Rinnegan
7) Infinite Tsukyomi time!
Summary...
Kakashi with Mangekyou Sharingan > Tsunade
Kakashi without Sharingan < Tsunade
Kakashi with 3 tomoe vs Tsunade would be epic!
I could honestly see it go either way