Sure, why not.
It does.
It's basically the standing power attack from oblivion that does higher damage.
Yeah, I figured it would do something like that. By doing more damage, you get the "finishing" move a bit earlier, i.e. you kill your enemies a little faster/easier; think Vorpal from D&D. How do you know that though?
And YES, I plan to, but only if it works for two-handed weapons which btw can anyone confirm wether or not it does? Slicing someone's head off with a long sword is cool, but CLEAVING someone's head off Aragorn style is where it's at.