Cold Steel passive

With the Thornmail and Randuin's Omen reworks, Cold Steel is now a unique passive on both items. As a tank, you'll generally want both items to combat Vayne, Yasuo and the like.

Would it be possible to nerf Cold Steel's base value but make it a non-unique passive? Too busted? Thoughts?

Perhaps the new Cold Steel value would only be around 10%, but the passive is no longer unique. It feels kind of bad to essentially have to build both items to get Grievous Wounds and the 20% reduction on critical strikes only to have a passive wasted because it is unique.