Heart Grown Cold

[Theo]

I agree with Konrad's reasoning. CoE ruled differently if the site was tapped (presumably the case from playing the faction):

*** No Strangers at This Time prevents a tapped hero site from being removed from play by Heart Grown Cold.

This seems to have been led by the question into ignoring that the sites must be exchanged (MEWH). Underlined portion seems wrong:

...
So HGC forces my opponent to replace the hero Dol Amroth with the minion version. But it's tapped, so then it would go to the discard pile.
...

I would think the tapped hero site should actually return to the deck and not be discarded because the minion version had to be in the deck for the player to have played the hero version in the first place. Once the switch happens, the minion version can't be targeted by No Strangers at This Time and should be discarded.

So CoE seems to have issued errata for No Strangers at This Time (later upheld two more times), perhaps justifying it as the context of MEAS not having a concept of site replacement?

So take what you will! (Good Question! )