"GfK floats another reason for flagship fatigue: vendors aren't giving consumers the features they really value. GfK's consumer panel cited "good battery life" as the most important feature of a phone – but batteries have got smaller this year. Meanwhile, the company notes, "water resistance has become a feature of many devices over the last 12-18 months, but this doesn't even make the top 10 of most important features when buying a new device"."
All of that. And...suprisingly, regular updates/patches would be a good pull. The new branded Nokia phones are making a big thing of this, and Blackberry.