As a clan leader I have had some troubles with having temporarily inactive members during a war and keeping track of who is active in the clan. It would be great to be able to see when the last time a clan member has been active and have the ability to hold a member out of war. Another nice addition to see would be another clan rank to show they are safe from being kicked but with little or no more power than a regular member. And finally longer clan messages.
Another cool feature that would be nice to see in the game
Another feature that would be nice is ready for war button that clan leader could click once his clan was done preparing for clan war, then once the clan you was fighting against clicked ready for war the timer would skip ahead to allow fight to began, instead of having to wait the full 24 hours before war starts.