Yes but why? Why does it have to be her and not the woman he did marry?
The prophets have that retarded cylon thing going on where they just make people do stuff with no seeming understanding of the effect it has.
I dunno, looking at the bigger picture and it seems the Prophets were messing with Sisko all along. Firstly they spew out that claptrap about having no clue about linear time, yet one of their brethren went down to Earth to possess a human woman so just she could mate with Joseph Sisko. I think the Prophets are rather familiar with linear time but they forced Sisko (in his first face-to-face encounter with them) to explain to them what linear time is. Really it was a clever way of getting Sisko more used to the Prophet's way of seeing time and the universe.
With each year the Prophets gradually moulded Sisko into becoming their Emissary. It makes sense because if the Prophets had told Sisko EVERYTHING in one go, it would probably have been a disaster giving Sisko's emotional state and the way he still grieved for his wife at the time.
The funny thing is that the Bajorans view the Prophets as gods, but the Prophets don't seem to view themselves
as omnipotent. So this whole Prophets vs Pah Wraiths is not some war of the gods but war between two non-linear races who have two very different ideologies. The Prophets seem content to sit in their realm and not use their powers to change the universe (except for the defence of Bajor), whilst the Pah Wraiths want to abuse such powers and destroy all life that is inferior to them.
The bottom line is that all this mythology stems from the Bajorans, in other words the Bajorans made a faith out of the Prophets and not the Prophets commanding the Bajorans to worship them. The Prophets say they are of Bajor which must mean they guide and protect the Bajorans, but not to the point where say the Prophets would say erase the Cardassians out of the timeline to ensure Bajor was never occupied, because that would be a gross abuse of the Prophet's power. Hence the Prophets send down orbs and speak directly to a few Bajorans who go on to write scarred scriptures.
I guess the Prophets did all of this because Bajor is imprisoning the Prophet's most dangerous foes in those Fire Caves, which is quite a risk on Bajor's part; something the Bajorans had no say in by the looks of things. So the Prophets decide to look out for the Bajorans and ensure those nasty Pah Wraiths don't break free and destroy Bajor. Though the Prophets were definitely off the ball when that Keiko Pah Wraith almost snuffed them out. Unless the Prophets foresaw it all so presumed nothing would happen as their foes are still bound to linear time, thus O'Brien double-crossing the Keiko Pah Wraith was destined to happen.
So despite all the mystery, there is a certain logic to this... The Prophets appear to know exactly what they're doing and they have this grand plan in motion...