It was a big part of the Pioneer metagame before The Lost Caverns of Ixalan , but it was pushed out due to a horrendous matchup against Amalia Combo
Ultimately, while Magica has a very cool and unique effect, I don't see the deck she wants to go in being very consistent, so I think she is a relatively mid card
Key cards reference FF lore & scenes, such as Zack's sacrifice, Cloud's Limit Break, & a Ferris Wheel date
If you've got her, people will get their swing on elsewhere
I briefly considered running Rampage of the Clans in my Clue token deck, since the deck generates so many Clues and Treasure tokens, it would be sweet to cash them in for an army of 3/3's at instant speed
Plus, lots of decks actually abuse them, by tapping a Howling Mine to turn it off, using a card like Fate Unraveler