When did we decide that the Seanchan prophecies were wrong? We've seen at least two that were right - Lydia's foretelling (which proves the talent is present and acknowledged in Seanchan) and the one Tylee recites to Perrin about the Wolf King and the Fox marrying the Raven.

And then we have the Shadow's prophecies - which we haven't seen that much of, but which seem to directly contradict the Light ones. They can't both be right, can they? Obviously both are possibilities and it's the actions of the characters that will define which come to pass.

So some Seanchan prophecies are correct, and contradictory prophecies exist and are apparently accepted as equally valid from a narrative point of view. Why, then, must we assume that the Seanchan prophecies are automatically all wrong? Perhaps he does need to kneel to the Crystal Throne, for some reason we don't know of yet.