I initially read this as 'power 3 or less', which would make it comparable to
Complete Disregard,
Grotesque Demise, and other small creature removal.
....then I read it again. CMC 3 or greater makes this a very different card. White has some similar cards, but they're usually based off of power.
Despark is probably the closest direct comparison. Alternatively, compare
Disdainful Stroke, which sees a decent amount of play.
The main draw to the card is that it will always be a tempo advantage - spending two mana to get rid of something your opponent spent 3+ mana on. I don't know if this will see play over
Fatal Push in Modern, and there are a lot of other rivals for the slot at instant speed (
Doom Blade,
Ultimate Price, etc) - the main question would be whether exile is worth sorcery speed, and my guess for that would be 'no'.
Definitely seems playable in Standard though, and very solid in Limited.