While I'm sure it's too late for Shadowbringers, a thought came to me in the other RDM thread:
  • Remove the damage of Displacement, replacing it with enmity control or CC
  • Replace Enhanced Displacement and Engagement with "Enchanted Corps-a-corps": When you have at least 80 Black Mana and 80 White Mana, the potency of Corps-a-corps increases by 200
That way you still save Corps-a-corps for when you're about to use your melee combo anyway, rather than using it on cooldown, making the damage just an addition to its primary use as a gap closer for your melee combo.

Could even use the admittedly very cool Engagement animation when Corps-a-corps is enchanted.