Huh, I found the Mage one to be the simplest so far. Maybe it was bad luck on your part and good luck for me? Or perhaps play styles just made that one come more natural for me.Ok your mana curve is really high. As a ramp druid you should be playing wild growth. That's how you are suppose to get your big minions out sooner. Savage roar is for when you also have force of nature to combo it with and you are not playing a token style deck so it is kind of useless. A harvest golem would help you more as it would take some early game harass out. I would get rid of the novice engineers. You have card draw with the blood mage, wrath and ancients of lore and if you switch a sunwalker out for a nourish then you will have plenty of card draw for the game. I would probably switch the shieldbearer out too.
Finally was able to get into the plague quarter after it was not letting me in yesterday. That mage challenge was tough. It was such a bad deck with minions that barely did any damage and secrets that were largely useless. I think I had a counter spell and a spell bender out on turn four (due to the scientist) and they never got triggered before I lost. All the other class challenges were relatively simple as long as you didn't get unlucky but this one you had to get extremely lucky that you were somehow able to deal with his doomguards.