I'm not sold on Assassin's Trophy. Sure, Abrupt Decay can be a dead cascade sometimes. Yes, the new card can sometimes kill a land, and your opponent won't have a basic to fetch. But it seems to me, like the good majority of the time in that situation, Assassin's Trophy will be a dead cascade all the same as Abrupt Decay. It's complicated, I don't think the card is strictly better, and I tend to think Abrupt Decay is more valuable.