It's a bad precedent to set, going back on something that they've stated so strongly for so long they want to be the case (gold cards are big, hard to kill cards that help close the game). I can't help but feel they would have been better off changing the values of certain cards to be silver instead, or even introduce gold cards that become silver when played.
Having said that I like that gold cards can be killed, but I'd rather it wasn't totally open - I think the compromise should be that golds can be hurt/targeted only by other units (gold silver or bronze). I don't think it's fair that a gold card can just be Alzur's Thundered, weathered down, or even Scorched. But most units wouldn't one shot kill (with the possible exception of the new Assassin card), or your spending a big enough resource that it seems a bit worth (another gold card, Nithral, etc). The only exceptions would be gold cards like Assassination, or the Dimeritium cards obviously. I would have it include special cards spawned from units, so you can't kill Yen: Con with a Alzurs pulled from Deathmold, for example.
Of course the change might be absolutely fine anyway. I'd just rather not see a removal meta myself.