I would agree it's not an easy challenge. It can take several attempts, getting the right cards in your initial draw is part of the problem. However it is possible to do it, I have to wait an hour before I can re-do it as I have ad option to watch- so my sympathy is not so great for those of you complaining about watching adverts to have another go. Remember you benefit from those adverts by getting free gems. I don't. You need to think about what you need to break through those chestnuts, such as, deadly, strike through, getting enough cards to stop damage to your hero. I think, one way it could be easier on these challenges is to give us an idea what the deck we use is comprised of. That way, I might have idea what cards I need to arrive in my deck.
Not it all challenges will be easy, as some people like to have some challenges a bit tougher to work them out. Card draw is the problem, no good getting a smashing garag on turn one. But, I can see they've tried to solve this by giving plenty of cards that give extra cards. Which to me, makes it unpredictable for those of who like to build a deck for specific cards. Like, using wing nut for going viral, or grave buster, for grave digger. All the cards you need to beat this challenge are in the deck, you just need to get them, ideally in the right order. By the way I haven't done the challenge, as I'm on my 6 attempt. Now waiting another hour to do it. I don't need to do it as I've all 4 event cards, and I had the card issue on the first challenge of the week so I won't get a free pack for doing a weeks worth of challenges. I just don't like to be beaten.