Arcane Nullified X-21, in my opinion, is a fantastic card. It will be amazing in mech decks, of course, but I think it's strongest place might be in control. Druid, in particular, can use them extremely effectively I think. Against decks like zoo and hunter, druid can put these out early (like a much cheaper, defensive spectral knight). This allows them more time to play into their curve. Here's an idea for a control druid Deck I recently switched them into.
Arcane Nullified X-21, in my opinion, is a fantastic card. It will be amazing in mech decks, of course, but I think it's strongest place might be in control. Druid, in particular, can use them extremely effectively I think. Against decks like zoo and hunter, druid can put these out early (like a much cheaper, defensive spectral knight). This allows them more time to play into their curve. Here's an idea for a control druid Deck I recently switched them into.
http://www.hearthpwn.com/decks/126726-gvg-control-druid