Avons best Island is perhaps the games best: a beautiful, twisting crag, massing behind the flock of birds, stretching up over the midground waves, vanishing into the white above and the blue below
Of course, a dedicated Etrata deck will usually have even better ways to cheat this downside: phasing or flickering her out of play before the shuffle, attacking with copies of the original or copying the trigger itself, or even destroying the target with some other assassin in response to fizzle the shuffle
Any price barrier would be artificial (not to mention there are multiple sites which disagree on a cards value), and if a card dipped below and jumped above, people would get confused
Fleeting Memories: interesting
Flashing this in on someones end step is actually a really satisfying reflection of how this mechanic would work in a pinch, and you know I love when flavor meets function