Couldn't agree more - especially about no.2.
Considering human factor failure rate decreases tenfold between "untrained" and "trained", a veteran should have much lower chance.
And I agree with you!
A demon-slaying hero could trip only if the whole floor is covered in slimy demon blood - but he should be able to ignore the sprained ankle. But these examples were not given for a demon-slaying hero.
Considering I'm level -1 at best and the friend I mentioned is somewhere around LVL 1 or 2, these examples could be used for maybe level 0-3.
But... a demon-slaying hero still could overswing and hit & destroy an adjacent pillar, leading to the collapse of the ancient temple. Or jam the damn sword two feet deep into wall. Or even stick it so deep into the demon he loses grip and the sword sticks from the surprised demon's body
Considering the opponents he faces, even a miniscule opening can be exploited - missed step is much worse when fighting high-level enemies.
And yes, the worst part is if a system increases the chances of fumble the more skilled the fighter is. That needs some serious fixing (there are systems that lower the probability with increase of combatants' skill).
I'm not against demon-slaying legendary heroes. I'm all for them - but even those guys should fumble once in a while. How often? Definitely much less than us, negative level guys
EDIT: Also, I'm one of the guys who plays games where 5000 peasants die on battlefield... that's why I usually provide low-magic solutions/examples.
EDIT 2: @GreatWyrmGold: As someone who still gets tunnel vision during sparring, I agree on most points. I'm quite proud of my footwork, yet I stumble too often when trying to coordinate everything at once. Practice makes it better. So, complete agreement.
@Max_Killjoy: Apologies for the caricature. I agree that a productive discussion does not lie that way - and I'm off to tend to my games