The balance in Clash of Clans It refers to an aspect of the gameplay that allows you to identify if it is possible to win in any challenge having the necessary resources and skills.
By this I mean that in the end, a skilled player can defeat a village with all its structures maxed out.
If there is a structure or troop that was considered indestructible, the game would not be balanced, so some adjustments would have to be made, such as taking defense points from something and adding damage points to a certain soldier.
What has changed the most are the troops, especially the baby dragon and the yellow dragon. However the archers, goblins, wizards, Valkyries have also been retouched.
However, the ranges of weapons such as mortars, the burst speed of cannons and in general the damage and range of war structures have been adjusted throughout this time to allow a balance with the new updates.