Glide - I thought this would be wildly OP, but it's been fairly innocuous so far. I've played a number of games as DH, and the draw is definitely nice, but more often than not, I've found the Outcast effect to be something I don't want to happen. So often my opponent had less than 4 cards in hand, so I was helping him/her by playing Glide. Obviously, this card would be much better if we had a control meta, but this doesn't seem to be the case.
Mindrender Illucia - I thought the hand disruption would be insane, but (at least in Standard) it's been...fine. Each time it has been played against me, I topdecked a good card off of the opponent's deck and I didn't feel too sad about it. Granted, my sample size is crazy small (like...2), but it didn't feel as bad as I thought it would to have my hand ganked.
Cards like Glide and Mindrender Illucia single-handedly make me, as a Wild Control or OTK player, auto-concede against any and every DH and Priest. It's just terrible design that disables opponent from playing the game. It makes for impossible, anti-fun and infuriating gameplay.