Rather than getting it as an anti-heal item, I noticed most ap assassin get it to become beefy while still being able to deal burst damage. If it's meant to be a long trade anti-heal ap item, then nerf its AP bonus. If it's meant to be a burst anti-heal item, change the recipe so it doesn't give bonus hp. Imagine giving AD assassin high AD item with bonus hp. Remember pre-nerfed steraks anyone? Make it so burst assassins for both AP and AD have to choose between damage and survival, not getting the best of both worlds.
TL;DR change Morellonomicon to better fill a niche role.