Apologies for the bump.
Sneak attacks shouldn't always be one shot one kill because it wouldn't be fair that you could be a weak character who can kill a very strong NPC without actually fighting him.
What's not fair about it?
If someone's a 5'-5" tall girl weighing around 90 pounds and catches a 6'3", 285 pound dude off guard, hits him with a baseball bat over the head...
I don't care how tough the 6'3" dude is, he's going down.
Seems fair to me. Why should someone HAVE to engage in a "fair" fight? Should magic users refrain from using magic against warriors? Should warriors not use swords against magic users?
Stealth in general needed some work in the last game. One of the major handicaps to archery, among other skills, in Oblivion was that any action taken while in stealth mode would result in someone instantly seeing you, even if they had no idea what was going on.
As a Master Marksman one of the perks is that you can paralyze someone with a shot from a bow. I would also use paralyze poisons on the arrows. I recall shooting a target and every single time, despite that they had their back to me, I had been totally hidden, and they were now paralyzed, they would suddenly know exactly where I was.
More importantly perhaps, so would
every other creature within a 50' radius.
Something resembling the Dukes of Hazard would then take place, where I would take off like a bat out of Hell down the length of the cave or hall, giving as much ground as I could, taking corners quickly, and generally trying to shake my pursuit.
Even if I was several rooms away from the pursuers and had taken several turns - thus they had no direct line of sight on me at all, they'd still know where I was and continue to close in on me. Conjurers would get near me and although I was still hidden, they'd know exactly which room I was in. They'd then summon a monster and despite that I could normally hide from that monster easily, it would - upon spawning in the room with us, know exactly where I was an immediately attack.
This made the concept of "stealth" pretty preposterous.
If they simply improved the stealth system in the game and actually played through with it this time in testing, making it serviceable, it would not only be a significant fix to stealth play in general but would also have a major impact on swords (which get a 6X strike if someone is hidden) and archery (which gains a 3x strike if hidden).
An improvement in stealth would go a long way to improving at least two other skills as well.