Elves and Ringwraiths

[Neithan]

BUT- with the prophecy and a WOMAN killing the witch king, doesn't it seem that women, or at least Eowyn were greater than a man?

Not really, as pointed out earlier there definitely were female characters that were greater than most males; Galadriel, Luthien, and so on. But Eowyn was not that impressive, in fact she was quite weak. I think that Tolkien was making several different points by having the Witch King die in this manner.

First, that the weak can sometimes make the biggest difference.

Second, that no matter how great you are, you can not escape your fate.

Third, that you should not base decisions on incomplete information. Hearing the prophesy, everyone assumed that the Witch King would be killed by a great Elf Lord or by Gandalf, and so he let his gaurd down when fighting these "lesser beings" and was killed by a women and a hobbit.

All of these lessons can be found elsewhere in Tolkiens stories. The first is the main idea behind The Lord of the Rings. The second can be found when Eru tells Melkor that even Melkor's secret thoughts have their source in him. The third is found in the Mirror of Galadriel and the Palantiri.