Any reason you need 20 MP? Most camera experts would tell you that the number of MP doesn't really matter if the size of the sensor is the same--in fact, there may be some disadvantages.
The battery on the N5 is admittedly mediocre, but it isn't all doom and gloom as some people might report. With smart usage (like following these tips: http://forums.androidcentral.com/am...how-tos/298919-guide-battery-saving-tips.html), I can get through a whole day on one charge, with light-moderate use. If you get a wireless charger, it becomes second nature to place the phone on the charger when you're at home and not using it, making sure it's always topped off.
If you don't mind rooting a phone, you'll probably be able to flash some form of Android L on any of the major phones pretty soon after it's released.