Xposed framework and its modules have been among the greatest innovation of the Android community in recent times. The framework when coupled with modules can bring nearly all the features that we see in a custom ROM nowadays to any Android device with root access.
The latest custom ROM feature to be ported to an Xposed module is transparent lock screen, which was first seen in Paranoid Android. As the name suggests, the transparent lock screen feature makes the lock screen translucent (or partially transparent) allowing the contents of your desktop to be partially visible.
In addition to the above, the module also allows for a solid color or a different image than your current wallpaper to be set as the lock screen wallpaper. Head over to this XDA thread to download the module.
Do keep in mind that the Xposed module will work on KitKat based Android devices.
If you are not already using Xposed framework, here is a guide on how to use it on your Android device along with its modules.