Overall, I feel like Channel Divinity is a rather well balanced ability. But one issue I have with it, and a lot of other abilities in 5e, is that they don’t really scale based on ability scores. Instead, we simply get a flat three uses: once a 1st level, twice at 6th level, and thrice at 17th level.
Thus, I propose that instead of the current progression, Channel Divinity should be usable a number of times equal to the cleric’s Charisma modifier per long rest (minimum of once).
Thus a cleric can have at minimum one use of Channel Divinity but potentially up to 5 (and more!) should he or she choose to improve their Charisma score.
I selected Charisma partially because older editions of the game, such as 3.5e, scaled Turn Undead based on Charisma. Not only that, but Channel Divinity represents a cleric directly interacting with his or her deity, and force of personality seems quite important for this task.
Of course, the cleric’s Wisdom modifier is another viable option instead of Charisma but is decidedly less interesting.
Number Three, Never Forget 