Only because of what it takes to add that where it is... You dont just add the extra and continue with production... It would need to be tested... The big thing would be a crash to see what happens... Like I said just a guess here Im betting that the new F150 will be in 2015
maybe Ford tested the frame in initial R&D with the thicker inner wall but decided from a cost and engineering standpoint that it wasn't entirely necessary at the time. for all we know, this could have been a consideration of thiers long before any frame bending issues and they just decided to make it happen in light of some of the bad press the Raptor frame-a-geddon caused.
this is all assuming the change was made in response to Raptor frame bending issues which for all we know it has nothing to do with it and it's merely a variation in manufacturing which has no quantifiable effect on structure or crumple zone.