Doing between x and y in a range of damage isn't really the same as doing no damage whatsoever, particularly in sneak attack situations.
Except for sneak attack, it's exactly the same. The results are determined by RNG, based of the values of weapon skill, block/armour (block doesn't work the same way though), and weapon in both cases. The frustration in Morrowind comes that the game didn't explained you why : "Hey there, you slipped on that rock and failed that sword attack", and just bluntly said you "Miss".
If we're going by realism standards, why does my gun get more accurate as my gun skill goes up? Is it that I learn to compensate for misaligned sights? Why not just be able to adjust the sights then, and if that's the case wouldn't that be better off as part of the repair skill?
It's your character's evolution. Would you shoot as easily a target the first time you wield a gun than after years of training ?