Hmm, so do you think tanks who build Frozen Heart are thinking, "That Ashe is getting a lot of attack speed. If I cut it down by 15%, we win!"? And do you think that Ashe is thinking, "Oh crap, their team has Frozen Heart, I'm worthless now!"?
No, I really don't think so. So your point about this item only being implemented because there is a need to suppress a monster caster is missing on me. And like it or not, this comparison is valid.
What that tank is thinking is, "If I get Frozen Heart, I'll get mana, armor, CDR, and it will help to slightly decrease how often I will be auto attacked."
So in this case, most likely the stats will still be the main draw and the passive will be a useful way to deal with a situation. Or at least that is my goal, which I may not be achieving. For this reason, I do appreciate the discussion, but it doesn't seem like that's the discussion you're interested in. Seems more like you're just saying it won't work, ever, so trash it.
I'm looking for things like, make it scale by level, make it an active effect, give it a small range, make it a debuff that is applied when the target deals damage to the wearer, and it lasts for a duration, ...