Steelix=dead. Jumpluff=Maybe dead.
Apart from that, there's really not a whole lot that it really just destroys. In this metagame, people run off of 1- or 2- energy attacks for he most part, so Zoruark won't really give you that much much of an advantage. Take Scizor Prime, for example. 30 damage for DCE, which is probably going to be lowered to 10 mid-game or even 0 if Scizor has enough Special Metal attached to it. Then there's Magnezone Prime. This deck would not be based off of lots and lots of energy, which you would need to beat Maggy. The problem is that most decks are based on their main attacker's attack and build a deck around it; the problem with Zoruark is that you don't know what the attack will do. Sure, you can add, say, rainbow energy, but that'll help with Scizor and not much else. You'd have to tech against too many decks, and a good rogue that you're not prepared for would just wipe a deck based on Zoruark out.
There are two ways I can see this card being used: as a starter and as a tech (but not in its own deck). If it were a starter, any card you want for 1 {D} isn't bad, particularly if you're running a deck already with dark energy (eg Umbreon). Its 2nd attack, too, isn't that bad, particularly against Donphan Prime or Steelix Prime (of course, Donphan OHKOs Zoruark for 1 energy, which isn't good). You just need to keep in mind that it is a stage 1. As a tech, it would be useful against Steelix Prime, but there's already Blaziken FB X for that, so I'm not sure how much play this card will see.
