Does this seem forced? Black has very limited direct damage. I wanted to make a spell with Espionage instead of only creatures, and this was the first design that came to mind. I looked at it for a few minutes trying to make it more black, and came up with the perfect solution.
Once I added the lifegain element, the card felt infinitely more black. It costs two more mana to cast but it resonates with one of the iconic black mechanics, life drain.
Edit: Here's Rogue's Treachery with the new Espionage wording: