John T, I suspect it depends on the wing/engine interface. Back during the original development of the 767, I was a fresh faced young engineering working nacelle aero - and at the time it was my understanding that we only needed the strake for the engine out condition.
Since then, engines have gotten progressively larger in diameter and more closely coupled with the wing (the 737 being an extreme example of that). So you may well be correct that it now goes beyond the engine out scenario.
On the 747-8, the need for the strake was identified very early on, and there was a pretty good fight between the aero types and where they wanted it to go, and the mechanical types that actually had to make the location workable
