I don't post here often, so I'm sorry if this has been suggested, I read the required page first and didn't see this idea. I saw the feature on a different game and thought it would be perfect for clash. Basically after any attack (looting, war, etc) you can click on one of your army camps and just push a button that retrains all of the troops you just attacked with. They are spread out evenly among all barracks and all barracks finish in very similar time. I feel like it would not be a super difficult thing to implement to the game, and it makes retraining troops so much easier!
If anyone has any suggestion on how this could be tweaked or made better, I would love to hear your thoughts.