I think arrows should have limb damage bonuses but such bonuses should be massively reduced (or even removed) against heavily armored enemy or thick skinned enemy to stop tough enemy becoming easily assassinated. That said, only really head shots should be able to instant kill, chest shots should incur "bleeding" damage, leg shots should reduce speed and arm shots should weaken attacks. A bit like in fallout 3, tho not exactly the same and of course without V.A.T.S, tho even in Fallout 3 you didn't need V.A.T.S to do any of that, it just made it easier...
I also hope we have multiple levels of zoom. Sometimes, the zoom in TES 4 just wasnt far enough for those really awesome long distance shots
EDIT:
When re-reading this post, it sounds kinda stupid...i dunno
Possibly.... just possibly, because I can't remember zooming in oblivion, other then then zooming out into 3rd person what I don't think is the kind of zooming you are on about. It's unrealistic to zoom because bows don't have scopes, so how do you zoom? Anyway, Draw Distances are increased in Skyrim what should make longer ranged shoots easier. Also, I assume like Oblivion, in Skyrim arrows will be applied to gravity, meaning long ranged shoots will require you too shoot above the actual target where if you were zoomed, you wouldn't be able to see what you were shooting above.