OK, obviously the word emissary means an envoy or representative, so Sisko was the representative or link between the Prophets and the Bajorans.
But apart from that, what did the Prophets plan for the Emissary to do? Essentially Sisko did all that was planned in just seven years, so to me the Prophets planned him to:
- Protect Bajor from the Cardassians
- Protect Bajor from the Dominion
- Make sure Bajor is safe in the future by ensuring it joins the Federation
- Defeat Dukat (as the Emissary of the Pah Wraiths) and destroy the Kosst Amojan book
So in essence, Sisko destroyed/warded off all of Bajor's major and existing (even future) threats.
But apart from that, what did the Prophets plan for the Emissary to do? Essentially Sisko did all that was planned in just seven years, so to me the Prophets planned him to:
- Protect Bajor from the Cardassians
- Protect Bajor from the Dominion
- Make sure Bajor is safe in the future by ensuring it joins the Federation
- Defeat Dukat (as the Emissary of the Pah Wraiths) and destroy the Kosst Amojan book
So in essence, Sisko destroyed/warded off all of Bajor's major and existing (even future) threats.