But don't you see. That's the point that simple slashing or gun bursts don't convey in games anymore. It's getting across the point of the pure brutality of the act rather than the player not caring or laughing it off.
Considering that dismemberment and decapacitations have never been featured in a TES game before, it WILL stand out if someone loses his head (literally) in front of a mass of people.
Besides, how often do you see executions in video games that are not accompanied by cool action music, and that doesn't stand out from the rest of the casual killing?
Call of Duty 4 and Modern Warfare 2 are two examples. Both feature a lot of death, and both have execution scenes that stand out.
You don't have to make it more hideous to make the execution stand out - music, camera angles, and mood can make a beheading scene 100 times better than to take the easy path and just pick the most hideous and bloody execution method possible, to try to make it stand out.
Sneak attacking a bandit and sending him flying into a wall makes you laugh.
Paralyzing him and igniting him, letting you watch him scream as he burns to death, would still make you smile if nothing else changes, like music or camera angles.
It's not
what you do, it's
how you do it. Besides, what do you have to work with when it comes to a burning anyway? Increasing the volume of the victim's screams? Meh.