The cleric now. There is much more text on it in the PHB, but I'll have a go.
I caught a big one in turning undead. Apparently, the ability works against any number of undead as long as they are within 30' of the cleric. They really botched this. The ability works against any level of undead, no matter the level of the cleric. The undead just need to roll a wisdom save to resist, but any undead, even a lich turned by a 1st level cleric like this, will be turned if it fails. There used to be a table showing the level or hit dice of undead a cleric of each level can affect. The goal here is simplicity.
I would suggest a cleric can affect undead with no more than five more hit dice than himself, and a maximum number of undead, of any hit dice, be five times the cleric's level in hit dice. Thus, a 1st level cleric can turn at most five skeletons assuming they still have 1 hit dice each, or one skeleton and one wight if they're caught together. The player should get to decide if the greater hit dice undead will be affected first in this new matrix.
Okay, let's look at all the other channel divinities now. These are based on subclass, in the cleric's case which domain he picks.
Clerics of knowledge. Read thoughts should let the victim make a saving throw to resist the suggestion.
Clerics of life. Channel divinity: preserve life, should require a long rest (at least) to re-use.
Clerics of light. Corona of light should switch to be the channel divinity feature, except enemies only have disadvantage on saving throws vs. radiant damage. Radiance of the dawn jumps to the 17th level ability spot.
Clerics of nature, tempest, trickery, and war are fine.
Going back to the basics for all clerics, divine intervention should only reproduce the effects of spells the caster can actually cast (and nothing greater).
With respect to weapons, clerics can only use blunt weapons unless their god permits them to use edged weapons.