Dr. Strange writers have attempted to give him some defined 'spells' that he would regularly go-to, and which could be used to make a very specific spellcaster with, say, eight specific 'powers' (Crimson Bands of Cytorrak, Winds of Watoomb, Images of Ikonn, etc.).
But other writers have fallen into the trap of using him (and other magic-users) as deus ex machina and being able to do anything they needed to advance the plot, and, conversely, suddenly mysteriously *not* be able to do anything that would interfere with their plot. (Hence Dr. Strange, for instance, being able to teleport the Defenders across time, space and dimensions, and even crap out a magic ring of teleporting for Nighthawk *because he was bored of being asked for teleports all the time*, and then conveniently losing the ability to teleport at all when Bendis wanted to use him as an Avenger, because Bendis wanted to have scenes where the Avengers sat around talking while on the Quinjet flying to missions, which they couldn't do if Dr. Strange just teleported them there!)
With Wanda it would be even easier than just giving her a half-dozen or so regular 'Invocations' to cast, because she originally had one simple mutant power. Bad luck bolts. She could *reliably choose* what specific bad things happened to a target, thanks to years of practice, so that she didn't have to worry about waggling her fingers and giving someone a fatal stroke, and could choose something as improbable as 'every structural support, every beam and strut, every patch of glue or spot of paint, all reaches maximum structural fatigue at the same moment and the building dies!'
It's an insanely cool and powerful ability, but apparently some writers think it's 'too hard' for readers to understand. How stupid do they think we are?
Bad. Luck. Bolts. I mean, really, it's not rocket science!