Speaking of Cleric, I'm kind of shocked that a class with Wisdom in mind has one of their cantrips use Dex as hit/save (Sacred Flame)
It's the opponent's Dex that is used. That's how saves work.
This! I reckon if the opponent makes the DEX save he completly avoids damage. If the opponent is proficient at DEX saves he adds a further +2 to his saving throws. I must say that I don't have a problem with the ranged cantrip being weak with clerics, as they can hold their own in melee, while wizards and warlocks struggle at close ranges, to say the least.