Ok, me being the player who made that attack I thought i'd pitch in.
The Attack was actually a 6 shift evocation. 4 shifts for stress, 2 shifts for zone.
The Original idea was to fill the zone with a Electrical-Taser Field. Using Earth Magic.
Since there were only 4 targets to hit I described it badly making it sound like a spray attack, causing all that trouble with discussions and so on.
I'm of the opinion that 4 shifts of power are definetly in the realm of "Incapacitate but not kill" a target.
(Especially in the current case. Thinking of how the mercs were described as being well trained and equipped. They had freaking Flamethrowers and Rocket Launchers dammit
)
What i believe to be a useful limitation for Zone attacks is to take shifts from the attack roll out of the equation.
No extra stress from those shifts for Zone attacks.
Shifts from the attack are supposed to describe how well I've hit a target. When i fill a whole zone with an effect, how does quality of hit facture in?? Right... it doesn't.
So my Weapon:4 Zone attack would do 4 stress if it hits, no more. Regardless of how bad the targets rolled for defense.
just an idea.