Shield Debuff Item (mainly for ARAM)

ARAM players used to have a huge complaint about heals, especially Soraka and Sona. So they added a pretty awesome debuff on the map to reduce healing on allies. Good call for sure. But I feel like shields are the new broken defense in the game. I do not think there should be a global debuff on the map. Shields are temporary and require quite a bit more skill than a heal. But when you are against a Janna, Orianna, Karma team, it's a little ridiculous. Although if the resources to make a new item are too much, probably just a 25% debuff when shielding allies? Idk. My suggestion: Introduce an ARAM only item that works like Morellonomicon's debuff, except on shields. There are obviously a few ways this effect could be triggered: could be an active steroid on the user. Any champ they damage during the duration of the active will mark targets with a debuff that reduces shield amounts by half. Or it can be a simple passive like Morello's. Or even an area of effect dust like Sweeper, where anybody in the dust gets reduced shield amounts.

What are your thoughts? inb4 "omg it's just ARAM"