ive come up with 2 clan castle ideas.
1. the castle has room for troops on top of it, but its never used. what if there was an option to change the way your troops spawn into battle from the castle? the way troops defend your base right now is by running out to face their enemies once triggered. what if a new button was added to the castle, this button will be called "defend". when set to "defend", archers and wizards in the castle will shoot from the top of the clan castle, the range of the castle will change to 7 tiles, so the archers and wizards on top of the castle will defend from there. melee units will run out to battle once there are enemies within the 7 tile radius, this means they can help defend the archers and wizards on top of the castle. if you want all troops to simply run out and attack all enemy troops with the larger clan castle attack radius, you can set your castle to "attack".
pros: stronger clan castle defense
cons: shorter radius means your base will not be entirely safe if the clan castle is never triggered by enemies.
http://i.imgur.com/jxmmMjf.jpg