Everyone should vote for the ability to swipe down on the lock screen to open up the camera like in windows 8. It works very fluid and would be a great addition for those that don't have a dedicated camera button. Heck I have a dedicated camera button and would still love to have this feature. Please vote on uservoice link below.
Swipe lockscreen down to launch camera – Feature Suggestions for Windows Phone
Swipe lockscreen down to launch camera – Feature Suggestions for Windows Phone