Sorry, but that looks more like an artist's vision of a die shot than an actual die shot. The TRM is pretty clear that it's an A15: http://i.imgur.com/Fvh2KVT.png

Core size isn't just a matter of the number of gates, but also their size. One important tool for reaching high frequencies in chips is to have gates that drive more capacities load be wider and therefore higher power. But if your goal is to have an architecturally identical core that's lower power one of the tools you have to accomplish that is to not do that. There's probably other ways to shrink a core at the cost of performance, as well.