Kurotowa
Legend
You are, I fear, absolutely correct. I hadn't fully gamed out the interaction of durations and initiative orders. The Warlock can never personally benefit by attacking a Paralyzed foe, outside of Readied Action gimmicks, and even allies only get it if their turn lands between the Warlock and the foe.Except this tactic will never work for the Bladelock. The Putrid Spirit takes its turn immediately after you finish your turn. The paralyzed condition only lasts until the end its (the targets) next turn. Meaning the Bladelock will never get a swing at it while it is paralyzed. Depending on initiative rolls your party may get some swings at it, which can still be great, just not the Bladelock.
So it's still a powerful action denial, but it's a lot trickier to use to set up melee attackers for easy crits than I'd first thought.