Adventure wing or packs?

I am new to the game (3 weeks since i started playing), I am trying to build a tempo mage since I have most of the cards except 2 legendaries, flamewakers and mad scientists. Since mad scientist is being pulled off i wasn't worried about getting him but my issue is that flamewakers are unlocked until the 4th wing of Blackrocm Mountain and atm I only have 400 gold so since I am new I would like some advice if I should save gold all the way until unlocking the 4th wing or I should buy packs and find a replacement of the flamewakers? Thanks for any advice!