For things like AI it's harder to do a "sliding scale". This is why I don't like this poll. I'd rather have a notched selection that actually changes the difficulty, not damage taken and given. But if they are going to do things the same way as Oblivion then there is no reason not to want a sliding scale.
It'd be simple enough to do a sliding scale with five "notches" on it for Very easy, easy, normal, hard and very hard. Each "notch" changes the difficulty of things like AI and detection and challenges (mini-games, lock picking, persuasion). The space between the notches increases the damage done to you and decreases the damage done by you within the general difficulty setting represented by the notches.