In general, I feel like very loose narrative tools result in more railroading than GM interpretation of traditional RPG mechanics. It might seem counterintuitive, but the reason is that if a GM has a story in mind to tell "at" the players, narrative systems enable that. If the PCs are only supposed to fight the BBEG at the end of the adventure, after finding the widget, then it is easy for the GM to say some other enemies were alerted even though they decided to use their Very Loud Power too close to his lair. But if you use a traditional RPG mechanic that says the BBEG was in range, that's too bad for the PCs but really good for emergent storytelling. Now everyone, GM and players alike, are responding to an unexpected story prompt.I'll counter with the the thought that I really, really, don't want a mechanic that precise for whom might be alerted at what distance by what use of magic. The idea that the use of magic might attract the wrong sort of attention is an awesome narrative tool, and I don't want it sullied with numbers, if you get my meaning. I'd much rather use it as, to use some loose PtbA terminology, a harbinger of future trouble move, or even a harder immediate trouble happens kind of move. In both cases I'd want to use it either flat out in the case of immoderate use, or even better, in a case of failed but moderate use, probably with some sort of countdown clock.
What I don't want, or need, is a blast template. That's too cut and dried for me. Maybe a closer, lesser evil notices, or maybe the necromancer in the far heart of his dark empire does, who knows what might happen. I don't want to constrain a tool as cool as this with anything as plebian as a range. A rough guide might be in order, maybe, but the first time someone tries to calculate how many miles they are from Minas Morgul before they crack off a magic missile I've done something wrong IMO.