This is my first go at ranking up on wild mode. I used Zalae's N'Zoth Dragon Priest - such an AWESOME deck allowing for streaks and great survivability due to the dragon based taunts. If you are looking for a good wild deck, give this a try!
The early ranks of wild mode are really strange. I faced beast hunters, strange murloc paladins, etc...  
This deck got me to rank 11 with easy streaks over a couple of hours. I then used N'Zoth Paladin to get to rank 7... (will post that later).