Well......she was talking about Oz.

Now, that prophecy could be talking about Emma if they said it was all the realms. 

Also, a sorceress from another land (would come by cyclone) and unseat the greatest evil......

Now, if they do travel by Cyclone to Camelot it would be hilarious, but I don't think it'll be mentioned again, but it will be something to keep in mind.

It was talking about Zelena, the realm being Oz. But if this was a foreshadowing of the Dark Swan that would be awesome.

What if Camelot is WITHIN Oz? It might be a kingdom near

That would be awesome. A sorceress (Regina? Redeemed Zelena?) goes to Camelot/Oz via cyclon to defeat the darkness in Emma.

From what you post I think the prophecy makes sense the cyclone could be the darkness that Emma stabbed with the dagger, and Emma being both the sorceress from another land & the greatest evil the realm has ever seen due to her transformation into the Dark Swan indicating that Emma is fighting the darkness within her meaning the prophecy said the sorceress from another land would unseat the greatest evil the realm has ever seen.

That vortex could be the cyclone, but I think Emma would be the one who defeated the "greatest evil". I really think that in the end of all of this she's going to save herself somehow. She could be both parts of the prophecy.

I believe that Dorothy came back and drove Zelena out of oz, leading to the events of 3b. That was the prophecy.

And what happen in the first episode of season 5? They travel to Camelot via Cyclone.

I don't think it was talking about Dark Swan, but I do think that Glinda's prophesy is not done yet, and that Zelena will vanquish the greatest evil from Oz, I just think the greatest evil has not shown up in Oz yet. As Glinda said "you don't know what the book actually means".

Oooh I like the sound of that. They could introduce The Nome King, Princess Langwidere or Mombi.

I'd love for Zelena's magic to really be tested in battle.