Rasenagn>sword is it not? Raikage broke that same sword right?
The Raikage would take a normal rasengan too.
Let me clarify it a bit...
Tobi blocked the sword with one hand with no damage to him and his surroundings.
That same sword was also was also blocked by killerbee which required two hands and created a crater from the impact.
Raikage broke the sword because it was already damage from suigestu's other battles.
Minato thrusted that rasengan and slammed it into Obito. Narutos rasengan was not only smaller than Minatos, but it wasn't exactly slammed into Obito.
Kcm naruto's rasengan exploded, it sent Tobi's body flying into boulders.
Minato's didn't even explode....
My point is that we didn't see him use any but kamui.
Like he could of protected himself with mokuton, even if it's a little one.
Or use his huge Katon when charging at each other so that he can burn his ftg knife.
Any would of been useful besides trying to reach and touch minato.
I mean what is he going to do when he warps him?
He won't die inside dimensions, maybe a genjustu but it's not going to kill him.