Trying to rephrase this in a way that makes more sense than last time.

I think all armor items can work on any tank, but there isn't an MR item that can be efficient on every tank, if that makes sense. There's no Frozen Heart or Randuin's or Thornmail for MR that any tank can build without missing out on something. The closest thing is SV and while the bonus healing is good, you're not gonna notice it if you're playing a tank WITHOUT healing capabilities. I just think there needs to be an MR item that can be universal because it feels like MR as an item class is so specialized that you can't stack MR without being gold inefficient for a passive or effect you don't need or can't use.