As a note for you, Guiding Bolt and Sacred Flame work exactly as described in the DnD e5 Player's Handbook.
I do agree on the feelings you have for them, though. Usually, spells that use saving throws will still deal half damage if the opponent succeeds on the saving throw, so it feels confusing to me that Sacred Flame does not work this way. But it is indeed true to the rules of e5.
