Decks that planned to attack with him.

Decks that equipped him and don't have a way to recover him thus losing 2 cards.

On the other hand, a Brotherhood deck with Go Down Fighting wouldn't really care that much ...

While I do think that Haywire will put in appearances in Squadron or Equip based decks (I'm looking at you High Voltage) I was more referencing his new status as every combo players new favourite toy and Poison Ivy's bestest friend.

Unless I put a Cloak on Haywire! Then you can't do anything at all to my precious 1/2 0 drop!

In your faces!