I've found, in the game's current state, that Hex: Wisdom works best to help with Shadowheart's atrocious default damage cantrip and Hex:Dexterity to help support Lae'zel's STR-based pushing tactics or casters using grease and ice.
Yea why is Shadowhearts cantrip so bad anyway? Firebolt is good, Eldritch Blast is amazing, but you get maybe 55-60% chance to hit on a good day with Sacred Flame, and that's with the high ground.
Sacred Flame seems gimped compared to other cantrips. Or maybe it's just that firebolt and Eldritch Blast are so much better than all the other cantrips.