I like the concept of staggering, but the implementation with a couple of enemies was absurd in Oblivion, namely Clannfear and Ogres. Those two could 'stagger-lock' you, staggering before you were out of the first stagger and leaving you absolutely defenseless. I had a level 54 character fall, from 100% HP to death, because of this insanity, all because the foe managed to get one damn hit in. Occasionally I'd get staggered an annoying amount of times while taking on a pile of guard archers, but I suppose that's what I get for deciding to off entire towns, eh?
Other than the locking, I liked it for the most part. I only hope the chances of this are slim to none in Skyrim, as nearly 80% of my encounters with Clannfear have been ridiculous bouts of being staggered to death or near death before I could get a hit in or spell off to kill the stupid thing. Ogres are towers of muscle, so I kinda justify that as such, but Clannfear's staggering ability and insane lunge distance made them simply a pain to fight. There was no fun at all in battling them, and I can't say that for anything else in Oblivion.
So that's my two cents, take it or leave it. Moral of the story, kids: I friggin' hate Clannfear.
Oh yeah, the stagger locking was awful. Mountain lions liked to spam the pounce attack too, which usually led to a death by stagger lock. =P