Frost Queen's Claim

So after reading Riot's thought process on Frost Queen's Claim, I think they are heading in the right direction with it. Something still needs to be done about the active, but I have a different thought about how to get the item out of the mid lane and back on the supports where it should be (not that supports aren't getting it, but I want a way to stop mid laners from getting it).

My idea is to have the item get a 7 second debuff that disables ALL the passives (both the stacks and the passive gold regeneration) when a minion is killed. But it does that already right? I want to see this debuff stack for each minion killed. So if you kill a whole wave in two spells, you have put your spell thiefs passives on a 42 second cool down; enough time for the next wave to arrive and for you to begin killing minions again.

With a change like this, spell thiefs will return to the bot lane because there is practically no incentive to pick up the item if you are going to be killing minions.