it will be stupid of them part to add low level area for an expansion, a good example for people that seems to miss the point are wow (the one they take inspiration) exept pandarie that was a special case... wrath of the lich king: new continent, new city all high level. Burning crusade: new continent, new city, all was high level area..

like the name implies it, it's an expansion of what we have already! not a restart!