Instead of a new city, they can incorporate the different levels of heaven palace and make the heaven palace the next step after Aerie City. We can have new quest, bosses, armor upgrades, bonuses etc at each level of the palace. They will just need to expand the palace a little more for us to explore. We can even have world events like defend the palace against the horde of invading dragons. Whoever wins cw can be the king of the palace. At each level of the palace we can have new and more exciting events like quests that actually requires us to find stuff instead and do something instead of just defeating a ton of toons to complete the quest. This would also make heaven palace a week long event and change the nature of the current heaven palace. The Caribbean sailing can also be expanded to allow us to capture cities and islands instead of just a boring march during GW. This would also expand the scope and add another dimension to GW. There are tons of possibilities for expansion in this game.