Truth is we wont know exactly what is calculated without going into the engine coding, but I would bet that Bethesda did NOT drop the ball on this one and that executions only happen when it was calculated that NOTHING you could have done would have prevented the death, including moving away or blocking.
I can unequivocally tell you, this is not true. I have been executed multiple times when I had way more health than a regular attack could hope to touch, while moving in a way that would make a slow power attack impossible to land on me.
Effectively the game thinks you died at the very exact start of the animation.
Precisely why I call it an instant-hit power attack. When the enemy decides they want to do a finisher, the game checks where you are vs where they are, the length of the weapon, and the maximum damage it could do to you if an attack hit at this exact moment. It doesn't take into account what you could do within the time it would take for the weapon to actually hit you.
You are dead, the animation hasnt even played and you are dead as far as the game is concerned.
Exactly the problem. The game decides to make you dead even if nothing could have killed you when
all factors are taken into account.
Making low/no-armor builds unviable?
Making the game a cakewalk. The problem isn't the difficulty. I have no problem killing things. The problem is that I'll randomly die through no fault of my own from something that couldn't have realistically killed me. It's essentially as if the game randomly CTDs when I'm in melee range, forcing me to restart from my latest save (only difference is it gets to loading that save quicker).
3. stay away from enemies that can instakill you.
Basically every human enemy in existence, some dragons, etc...
It doesn't happen often enough that it's unplayable for me, but it happens enough to be frustrating and removing it would bring a notable boost to the overall gameplay.