Allow players to join public games via a game lobby rather than just private games via game IDs

Allow the game to have a configurable time limit for turns (ie 2 min). After time expires the turn is auto-played at random. Subsequent timeouts for confirmed disconnected players will increasingly decrease the timeout limit while the player remains in a disconnected state.

Allow players with authenticated accounts to be ranked on a leaderboard

When you end the game it isn't always clear to all players. The final game summary should include information about what the final holdings on the board included for each player.
The game should not allowed to be played after the game has been called.

Allow chatting in the game. Allow users to silence the chat.

Allow players to undo a turn/move.

In cases where decisions have already progressed all players must be in agreement before the Undo can be performed.

Allow users to create accounts with Facebook/Microsoft/Google/Twitter