From the childhood scene to her reminiscing, it's another beautiful scene, especially after the devastation Nibelheim had endured
Its a high-priority target for removal, so make sure you play a little protection or recursion to keep it around
The initial idea of Historic was that players would be able to continue to play their cards after they rotated from Standard, and adding a bunch of super-pushed cards each quarter had the potential to basically function like rotation, by making cards that players already had in their collection unplayable (from a competitive perspective, at least)
No waiting around for a tap ability, Callidus Assassin assumes something's identity and then it's off with its head
Loading your deck with the best instants MTG has to offer makes opponents play scared, even when your hand is empty
But I picked Norns Wellspring over these for a few reasons