[Raynor]

Originally Posted by obloquy

Gandalf knew that none could see the battle, so perhaps he was allowed here to unleash his latent potential.

Interestingly enough, he has no problem indicating the amount of power involved in this fight - nor even concerning the fight as Weathertop with the nazgul.

Originally Posted by The White Rider, TTT

Those that looked up from afar thought that the mountain was crowned with storm. Thunder they heard, and lightning, they said, smote upon Celebdil, and leaped back broken into tongues of fire. Is not that enough? A great smoke rose about us, vapour and steam. Ice fell like rain.

Originally Posted by The council of Elrond, FotR

But they closed round at night, and I was besieged on the hill-top, in the old ring of Amon Sul. I was hard put to it indeed: such light and flame cannot have been seen on Weathertop since the war-beacons of old.

Originally Posted by obloquy

So the power of a Ringwraith drawn from its ring trumps ordinary weapons wielded by individuals with less spiritual potency than that Ringwraith's allotment.

My own impression of the passage is that if even Frodo had an armour that protected him against a "spear-thrust that would have skewered a wild boar", then the Witch-king should have a similar, if not better, armour. However, I do note that previously Gandalf stated that
"- You cannot destroy Ringwraiths [by flood]. The power of their master is in them, and they stand or fall by him. "

Originally Posted by obloquy

the more powerful "spirit" ought to be victorious

I think that a counter-example would be the duel of Fingolfin and Melkor; Fingolfin was able to repeatedly wound his opponent, and I doubt we can compare their powers on any level. Also, Thorondor did some pretty good action there too, wounding Melkor without losing a feather.