Well, I have the copper cores in my car because regardless of any technicallity, I don't see spending $6 per plug when I'd like to keep my plugs replaced, rather than buying helicoils for plug changes every 100k.
Oh I suppose I should throw my 2 cents into the physics here. If the platinum plug makes a weaker spark, why would it be less likely to miss? If you are running a 5.0 with a good ignition, you don't have to worry about the lower voltage, and say running 10.5:1 compression would be much more likely to cause a misfire with a weak spark. Now of course, you could assume that it will not spark until there is enough voltage to arc period, which would mean it would just take a split second longer than normal to spark as the power builds.
Anyway, the concensus is still platinum plugs for the cars that weren't meant to run them stock are crappy, lol.