I'm not sure leyline works with this card. Shifter zerus is always shifter zerus in your hand, it displays a minion and then transforms itself into the minion only if you play the card. Right? So as long as this is in your hand, the game considers it is shifting scroll and nothing else. Right?
This will be a really good card in Arena. I call it, getting an additional Primal Glyph / Flame Strike / Blizzard / Fireball / Cabal Tome.... Yeah, there are a lot of powerful mage cards, and if you are not hard pressed, you can wait for extremly value plays
better Shifter Zerus for spells. It's more limited to mage spells which often are good.
I like this card in arena. You wouldn't choose this over a Primordial Glyph, but if you lack a board clear and choosing between this and a Frostbolt for example. I'd probably choose this for a chance at value.
"Most believe there are two types of people who go into a crucible. The ones who become stronger from the experience and survive it, and the ones who die. But there's a third type. The ones who learn to love the fire" - Sebastian Blood
This card is good because in the text say mage spell. So it is not a totally random spell. Mage spell are good so this card is good. I voted meta-defining. I think is very very good in decks like control mage when you have the possibility of keep it more than one turn and use it when you need it.