Morrellonomicon's GW applying when target is below 40% hp is counter-intuitive

Morellonomicon applying grevious wounds only when the target is below 40% hp is pretty illogical. It should be the anti-healing item, but the problem is when you have champions like and which are extremely difficult to drop below 40% hp it pretty much leaves them unchecked. A lot of times these champions can just heal through the damage and you'll struggle to drop them below 40% hp. I understand that Morellonomicon was overpowered and the better option to Athene's, but it should have been nerfed in other areas.