Remember, nothing here is fact, just pure speculation.
Since it has been figured that Utopia will most likely be the name of the next campaign, I'm guessing that the game will be Greek inspired because Utopia is a greek word. The storyline may be something similar but not totally parallel to the Lost City of Atlantis.
Also, it would be cool if something similar to the Olympics was incorporated into this.
Maybe guilds can form 4 man running teams and race other teams through mobs of monsters for record times.
For armor, we may see corinthian helms, greek/roman robes. Nothing will be an exact replica but similar.
My speculation/wishlist for Chapter 4.
Halc yon
Lothlorian Sassun