How do you think these places are going to work?  According to wiki.guildwars.com/wiki/Guild_Wars_2, Cantha and Elona are still significant places but are isolated from the rest of the world.  Seeing that they are also human-dominated places, would this mean that if you chose to be human, you could also choose to be Tyrian, Canthan, or Elonian?  I would definitely love to see something like that.  It's going to be an open persistent world, after all.

Then again, all of the races: Norn, Asura, Charr, even Sylvari hints that the game will be centered around Tyria.

Read the Movement of the World article if you want to know the fate of Cantha and Elona.

http://wiki.guildwars2.com/wiki/The_Movement_of_the_World 

 Though, it certainly leave a nice explansion shaped hole, if you get my drift. 

I think its safe to assume that the worlds of cantha and elona if not visited in the initial release of GW1 for whatever reason, will be visited in expansions as the situation within those parts of the world could certainly escalate or deteriorate causing need for action to be taken, however I would hate to see GW2 follow the same expansion line as GW1 Factions,Nightfall,EOTN.

Originally posted by Halo-Bump

 Though, it certainly leave a nice explansion shaped hole, if you get my drift. 

Which would be fine by me. :D

i read in a couple places cantha is shut off by the world and will not be playable

which is a pity, it was my favorite campaign

I do hope that there would be expansions taking place in Cantha and Elona... especially Cantha in particular, because it was by far my favourite campaign out of all the three. I could live without seeing even a hint of my favourite characters (though it would be extremely wonderful if we got a passing mention of them somewhere) but if we don't get to see Cantha at all, I would be extremely upset.

Originally posted by hekimo

i read in a couple places cantha is shut off by the world and will not be playable

which is a pity, it was my favorite campaign

Yes the sea route has been severed by (if I recall correctly) the very same dragon that is hunting Tyria as of right now. They didnt say it wasn't going to be playable they just said not playable in this upcoming GW2. As for elona, it has been overrun by Palawa with his own minions of death and will be based around overthrowing him, apparently he holds the crystal desert.