"Surrender" option in war
I think a 'surrender' option should be added. During clan war if one of the clans have gave up because they know they cannot win, then they should be able to surrender.
It will result in end of war so that new war would be started. It is better than waiting for battle day to end, knowing that the clan won't win under any circumstances.
Only leader shouldn't be allowed to do it. There should be a voting system in which members in war can vote if they want to surrender or not.
If a clan surrenders than a request should be sent to the opponent clan that if they want to accept it or not.