MArcomage

A very adaptive card... I like cards that "attack" opponents hand, if not replacing too much ;-)
As you cannot move it (by self) and it only works, when new, not that bad imo.
What I don't like is, that the strength of it depends on hidden play-mode. But there are many other such cards, as black market, barbz or confusion.

Surely it should allow common cards to be discarded?

If it were a typical match-discard, I would agree, but since it is replacing with a random card, it seems right to me that it should have a weakness. Not functioning against Commons makes this unique.

I like this one, also because it's not moving in hand

Edit on the card: Instead of a random card of the next lower rarity, it replaces the card now with a random card fromt he opponent's deck of the next lower rarity