Over the past 18 months, CEO Kaz Hirai has been on a mission to unify the sprawling empire entrusted to him into a more cohesive and focused One Sony. On the mobile front, that’s resulted in Cyber-shot cameras and Bravia-branded displays appearing in handsets like the former flagship Xperia Z. Today’s Xperia Z1 continues that cross-pollination push with an even more comprehensive set of borrowed features, including its headline-grabbing 20.7-megapixel Exmor RS camera. The Z wasn't a phone without its flaws, however, so the more pressing issue is whether Sony can continue building on what worked and solve what didn’t.