Calling dibs on an enemy on the clan war screen
I'm sure everyone has had this happen to him/her:
Scout an enemy base during war prep, decide who you'd like to attack, and build a suitable army for the base, ie building dragons for a base with poor AD placement, etc. You say in the Clan chat "leave number 6 to me". War prep ends, a friendly Clan member comes on after receiving the notification and promptly attacks your chosen target. Now you sit with a dragon army, and now you have to settle for someone lower or having to dismiss your entire dragon army as no one else is suitable.
My solution:
On the war screen during Clan preparation, add a button to call "dibs" on an enemy. When a Clan mate wants to attack your chosen enemy, a message pops up that notifies him that someone else has already called it. The Clan mate can then choose to still attack him, so this wouldn't cause problems where you call dibs and never attack, leaving the village unattackable.
The Clan leaders can, in the event where someone is spitefully attacking over dibs, sort that member out.
Thanks for the consideration of my idea :-)