It may have minor damage
While two mana for two cards each turn is definitely a good rate, there is a very real delay with Sylvan Library: it takes a whole turn cycle to actually do anything, which, as well see with the rest of the list, makes it fairly slow by comparison
By being able to lock your opponent out of casting spells of any one colour when she entered the battlefield, Iona may as well have read "your opponent doesn't get to play Magic." Spark it: Read our beginner's guide to MTG Jumpstart In a Modern deck like Gifts Ungiven - where the eponymous card lets you put Iona into your graveyard only to reanimate her later - she can enter play on turn four, and close the game from there
However, Im not sure how this impacts the game greatly as many of these colors follow already established Ink colors, meaning the card couldve just been included in the deck if it was one Ink color
There are a bunch of different ways to abuse the card alongside Landfall triggers and sacrifice outlets, so it makes for a reliable alternate win condition in decks like Aristocrats
I've enough of this, i can't play hero anymore, having absorbed my sister's blood magic, and my brother's secret of life drain