The more I think about this, the more I dislike the card against Workshops specifically. I don't think anybody here was really claiming this card is a Workshops killer, but I feel like soapboxing a little.
You're spending three mana, which for you is 2 to 3 turns worth of mana development, to kill a single card which costs them 1 turn of mana development. If that card is an Arcbound Ravager or Walking Ballista or Hangarback Walker or Precursor Golem, they still get some value out of the card, so you're trading 1 of your cards for less-than-1 of theirs. This puts you behind on both tempo and cards. This is actively bad against Workshop, you are worse off when you play this card, the same way you'd be worse off running Stone Rain against Lands or Fade from Memory against Dredge.
Basically, the card is just "not dead". Since this is constructed and we have to handle multiple decks, sometimes (often, really) we have enough even worse cards like Flusterstorm that "not dead" is a better alternative. Still, large numbers of these sorts of cards are a kind of "deck smell" (in the way that programmers use the term "code smell" ... I suspect there's a better term for magic, but I think it's useful ... something that isn't necessarily bad in and of itself, but usually means there's some problem nearby). The more of these you have the WORSE your Workshops matchup is, a deck with 40 Goblin Cratermakers and 20 lands basically couldn't win a game unless the Workshops player had serious mana trouble.