10 shift successful physical attack with weapon 5 means 15 shifts of physical damage. It very much means you hit him harder.
No, it does not. It means 15 shifts of physical
stress that may or may not translate into any physical damage at all. How that stress manifests is
entirely up to the players and the GM. There is nothing that says it has to mean that the weapon actually makes any contact whatsoever with the target.
Remember you figure out the action, before you roll the dice.
You figure out your intent and how it works mechanically before you roll the dice. The actual, narrative result of the attack is decided after all the dice are rolled and the mechanics are decided. Nothing should lock you into a lethal result, unless the player is getting a fate point because that is a compel. Otherwise, the player
always chooses how a Taken Out is narrated. The game is very clear on this.
So when some one decides to attack, with potentially lethal force, they've already made the choice to hurt the person, possibly to the point of killing them.
No. The game isn't real life--it stresses repeatedly that the player has the final say in how any Taken Out result plays out.
To take it to real life, when you shoot some one, you have a real chance of killing them if you shoot well enough to get them in the torso. To take it the Dresden fiction, he talks about how he holds back his power, before attacking, in order to prevent any chance of killing a mortal with magic.
The game is not real life. The books are not the games. In game terms, Dresden holds back because he's a high refresh character who doesn't have a ton of fate points to spend on buying out of compels or making invokes.
In my games, I try to highlight the consequences of my players choices. I won't automatically demand they kill someone if they succeed by that much, by I will ask them come up with a reasonably explanation of how the person is taken out.
You have to remember that "Taken Out" just means "No longer participating in this conflict." It doesn't have to mean the person is physically rendered incapable of acting, only that the person will no longer be physically acting.
If you want to give the players more narrative control over there own consequences, that's very much within the spirit of fate. But it's kinda out theme and tone for Dresden.
Not mutually exclusive. If you want to enforce an unintended consequence, that's probably a compel. Remember, Dresden is about dealing with consequences, but it's also about making
choices that lead to those consequences.
Or put another way, it's about the
characters getting bitten in the ass by the unintended consequences, not the
players. The fate system exists so that the players always have the choice.