You are not alone, I haven't been able to get the required dragon in the last several events. I usually don't play the events because I get bored and frustrated with the stalemate. 15 hours here, 10 hours there, 20 hours everywhere, alas no 4 hour common, that gets tiring and is definitely not fun. I even start to forget about it totally, and then the event is over. I started to believe in the last event that it wasn't even in the realm of possibilities, and the goal was to get me to spend gold to purchase it, but I don't give in to trickery. Ironically, during the events, I have been able to breed many rare and super rare dragons to trade. I've gotten so many super rares, over the common required dragon that I have over 1600 essence to craft something valuable.