People like to cite battery life as the reason Apple didn't allow third-party widgets in the Notification Center. I say that's not true. If the mere addition of widgets has a significant impact on battery, then so do push notifications and local notifications. The solution to the battery problem is this. If new data is available, the widget can be updated via a widget service. This is similar to how push notifications are delivered - they are sent to Apple, then to the users' devices.