What’s the biggest gripe that people have about the iPhone? Conventional wisdom says that many people are put off by the device’s comparatively small display size, which explains why Apple will likely release two larger new iPhone models this fall. However, a new survey of more than 1,000 smartphone users conducted by uSell.com has found that it’s actually stronger battery life that iPhone users crave more than anything else. FROM EARLIER: Samsung’s new iPhone-bashing ad is more true than Apple wants to admit. Results of the survey, which uSell.com provided to BGR, reveal that 37% of respondents most want to see Apple improve the iPhone’s battery life while just 19% said they wanted the iPhone to get a bigger display.