Darkness is your Friend - Sometimes
I have been testing some more and I decided to tweak the darkness mechanic even more. Now you can no longer find secret doors in the dark too. Also, in order to gain a stealth advantage, the game will compare your armor's sneak rating to its protection level. Only if your sneak exceeds the protection will you be able to take advantage of the darkness.
In additions to this, you can actually have a negative sneak value. Previously it could not go below zero. So having heavy armor and additional protection like plate gloves and boots, will make it harder for you to sneak.
There are a lot of advantages to using darkness, but I felt they needed to be balanced a bit more. This way each piece of armor you choose will have an effect on how you play. Also, items that can increase your sneak more will become more valuable to players who opt to choose the path of stealth...