The worst thing about Windows Phone screens, brightness settings, will be improved in the Cyan update

Windows Phone supports only four brightness settings: low, medium, high, and auto. Anyone wanting to have more detailed controls have sadly had to do without, but that will change soon on more Nokia handsets. The Nokia Cyan update heading to Nokia phones in the future will have the option to adjust brightness along a sliding scale. This is a marked improvement over the current options.
The difference between 50 percent brightness and 65 percent brightness is noticeable and ideal to balance the needs of battery life and brightness. Forcing users to switch between three standard settings prevents them from getting into the middle grounds. The Cyan update has appeared in a screenshot that shows that option. Rather than have a singular sliding scale, users will be able to move the scale to define the brightness for the low, medium, and high settings. The Lumia 630 is currently the only phone that supports this option because it lacks a light sensor, but more Nokia phones are set to get this feature.
If you've ever used an Android or iPhone and switched to Windows Phone, the lack of fine-tuning the brightness settings has been one of the biggest complaints about an otherwise typically great display. I've complained about this as early as the Lumia 920's release and the problem has persists nearly two years later.