A Few things I thought about when I was thinking of sneaking factors in Skyrim and if maybe they will apply to TESO.
So we know medium armor will give sneak bonuses and make you more effective. This could be compared to Skyrim where light armor had no sneak penalty but heavy armor made your sneak much less effective. But also weapons did the same things. Daggers / bows = no penalty, 1hand weapons gave a small penalty and 2hand weapons gave a large penalty. I'm thinking TESO may do the same but with bonuses like the medium armor mechanic. We could see something like Daggers and bows give a 10% sneak bonus, 1 hands weapons (axe, sword, mace) give 5% bonuses and 2hand gives no bonus or even a penalty. maybe even dagger itself will get a 10% sneak attack damage bonus.
Now in Skyrim sneak attacks did double damage (compared to a basic power attack). When you perked in the sneak tree you could have the following for your sneak attacks: Bow = 3X damage, 1hand = 6X damage and dagger = 15X damage. I'm hoping we get something along those lines in TESO, I know they would have to be toned down alot for PVP but I'm hoping there is some kinda of big opening damage for a dagger sneak attack (backstab).
From what i heard sneak is only attached to the medium armor skill tree and it DOES NOT have its own skill tree. this kinda has me worried to how we will be able to enhance or perk in sneak itself. Speculation is that the Nightblade class will have a skill line that focus's on sneak attacks and flanking.. which i'm fine with and would go that route but I think there should still be a way for other classes to really help their sneak and sneak attacks beside the medium armor tree.