Ok, lets use the example you brought to the table. A tree is not a moving, dynamic object. It's a stagnant, permanent object with no ability to "not" be hit.
I'll buy that.
Say the tree is attached to the back of a truck, sitting in the bed, ready to be hauled away. You swing at that tree, but the driver gives the truck some gas, causing you to miss the tree.
Did that miss happen because of your "skill" with a longblade?
No, you missed because the damn thing moved.
A players agility, in my opinion, should be the only factor in whether you actually "miss" or not. And by miss, I mean simply not even connect the blow.
Like you said, a moving object is hard to hit. But anyone with a brain can hit something that is not moving. Has nothing to do with your skill.
Enemies that can strafe/move, and their agility should effect how hard they are to hit, not your personal skill. I never mentioned a game where every blow hit, I was simply talking about the pure mechanics of the system, where if a object is there, and you swing at it, you're going to hit it.
Now throw in radiant AI into the picture, dodging, strafing, etc, sure, you can miss. But THAT should be the only factor. Just have to apply the two sciences and come up with that result.