Refill system for troops and spells
How about an extra button to each of the 3 quick train presettings to activate/deactivate automatic refilling of the specified troops?
To me this would be more useful than the Train button as my queue is usually full all the time, therefore no space left for training.
Think about it. You donate something and it automatically fills up exactly what you donated. Or how often it happens that you don't use your wall breakers or spells? So, no need to train even more for the next raid.