I know for one that when buying troops, it can be a labourous task when farming. This is when I had the idea of an overall troop builder interface.
Each available troop has an amount setting, which sets the target number to be available in camps after production has completed. This can also be set to infinite. Troops will then be built from the lowest queue available in construction buildings. There would be a build once, or continious build modes available for the queues.
It really is that simple.
Use case:
BARCH, setting target barbarians and archers to infinite build.
BAM, setting minions to 20 max, and infinite archers and barbarians
Balloonian, setting balloons to 28, Minions to 30, and trash/pull troops to fill camps
This would mean that you can set your tactic ready, and continuily build. Increases the amount of times you can attack, and reducing human error in building troops (Building a couple of extra wall breakers by accident for example)
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Resource Boosting
Further topic, an option on all resources of a type to boost all resource gatherers of that type for x gems. Hell even give a discount for boosting all, that would make a lot of people happy