Artifacts should can exchange with gold, if possible?
Also there Should be a way to mark a castle so that it wont get enlightened ever besides location
A message should come up when somebody logs off or goes AFK if their online status is not hidden.
When you put resources on offer, you should have an option to refuse to send them to enemy alliances, or charge a higher amount of gold to enemies.
The most stressing thing that can happen is to log out by some reason and lose some long text you're about to send or post.
You should be able to reorder your cities, so that instead of them appearing in alphabetical order, they can appear in the order of oldest to newest when you use the next/previous city buttons.
You should be able to research resource node destruction time. It is very annoying that the time it takes to clear resource nodes is 2 hours regardless of your construction speed.
Palace-related achievements for players, mainly for the title of the player info window. For example,"PlayerName of Compassion," or "PlayerName, the Compassionite,"
Regular town custimizations like the Castle custimizations.
Make Castle custimizations free. A simple appearance changer that doesn't effect gameplay whatsoever should not cost any funds.
A shorter version of the game that can be played in 4 months or less.