I'm still not convinced that this attack is sufficient to Take Out a target in this manner. After all you have Mild, Moderate, Severe and Extreme Consequences, at the very least to overcome with Shifts before you can Take Out the target. And heck he might Concede, leaving you with a lot of left-over shifts to absorb somehow.

To address the OP's question with regard to the Intimidation factor of this particular variant of The Fastball Special, I would use spin generated by the roll as my base, and go from there. Now keep in mind that I'd look at the Ogre's total Stress, plus what he could absorb with his Mild, Medium, Severe and Extreme Consequences, before being Taken Out (2+4+6+8=20, plus 5 Stress to allow for high-end Endurance, though not Inhuman Toughness) would give you a +1 for Spin.

Of course I have had a sniper actually cause sufficient Stress to deal an Extreme Consequence, in one attack.

However, it also means that you cant (without GM intervention) just say that the weapon 10 evocation you hit the group of mortal gangbangers with left them all miraculously alive. Thats not really within the realm of reason, considering that a weapon 4 attack is a grenade (which granted, people have survived), I cant really think of something that would constitute a weapon 10 attack.

My point is you can "be forced to kill" if survival is not within the realm of reason.

Otherwise I find your post to be very interesting.

Actually, if you are being "forced to kill" by the mechanics of the game, you can figure that an NPC with Average Endurance has 3 boxes of Stress. Plus 2 for  Mild Consequence, plus 4 for a Moderate Consequence, plus 6 for a Severe Consequence, plus 8 for the one (and only) Extreme Consequence means that you have to do a minimum of 23 Shifts of Damage in order to guarantee a Taken Out result which you can assign the value of "Killed." This is established as a difficulty for magically Transforming a character (and it is pointed out that death is a Transformation. So "accidentally" killing another character is not going to happen. However this is just my opinion (based on the mechanics in the book) and I could be wrong.