Lack of injuries and most of the team having the summer off. The ones who haven't, haven't been needed so much (Demi and Zabaleta) due to Sagna and Mangala looking great. Kun is still not 100% sharp but takes him a while to get to his level sometimes. He's still better than the rest even at 75% anyway. Fernandinho has the engine of two players, which helps Toure.
Most important thought is moving Silva. He is constantly pulling the strings now. Him and Toure just do what they want with the ball. And Sterling coming in has given Kolarov and even Navas more space now. We have proper width on both flanks so teams can't be as compact against us, which means Silva has more gaps to pick the ball up in.
It's still a long season. I think we are seeing a bit of a transition as well. Even though he scored a very good goal, i felt that when Nasri came on, it almost felt like he doesn't really fit anymore. He's less interested in performing his team duties when we don't have the ball. He's still a very good player and i hope he stays and battles, but i feel like he's got a choice to make now. The team are really starting to press off the ball, and Sterling and Navas will do this with pace. Nasri won't. He doesn't look as hungry as the players who have started. I also think Bony is an upgrade on Dzeko. He does everything i wanted to Dzeko to do.
So to summarise, it's pace and hunger. And Silva.