In the other thread about new zones, The Reps basically told us "We've got a lot planned, Theres no room For a new expansion."
I asked one of them "IS there any chance we might see an Expansion after this timeline finishes out? or next year, year after?"
I got no response
Its safe to assume that no, We'll never see another new Expansion or Continent/Zone ever.
Maybe 1-2 Re-colored Battlefields (The Concept art of the Giant Crystal Area comes to mind, My bet is a recolored Avatar Arena, or something similar to Riverne), but i don't think we're every going to see another Expansion-level amount of new Zones ever again.