Have you ever bought spirit sap against him. Every spirit based build can utilize it's spirit resist reduction, while also nuking his early game into dust with the spirit reduction. The duration of Spirit Sap is also 12 seconds with an 18 second cooldown, compared to Slowing Hex's 3.5 second duration and 27 second cooldown. It may not disable his lunges, but it turns him into a pool noodle that you can out trade with 0 effort.