Would definitely see play if it was 4/1. That way at 2 spells you'd break even and it'd be value after that. As it is, it's going to be too hard to have more than 3 spells in your hand by turn 3 consistently.
It’s one less mana. That’s a VERY good reason. Especially if your deck is very spell heavy. That said, Warlock runs a lot of minions so you probably can’t play this there. You probably need this to be at least a 3/6 to be really good.