stacee:
I'm sure you're aware tip stall is a known phenomenon in swept wing aircraft.
Yes indeed. As that characteristic was discovered about six decades ago (see Galaxy Flyer's point on the F-100), I think you will find that aerospace engineers have come up with a variety of ways to mitigate the problems of spanwise flow. Even as far back in history as the 1970's we were taught about slats, stall fences, et al.
I imagine the extreme alpha involved in this tragic case would make any washout irrelevant.
I am not so sure.
As you are doubtless aware, washout isn't the only method used to mitigate for spanwise flow.
EDIT:
If you look at this picture
http://t0.gstatic.com/images?q=tbn:A...MC_qkyAgvf5Khp
you'll see one way that design engineers addressed that issue.
On a different scale in a fighter of a generation or two after the F-100 Galaxy Flyer pointed to, this picture shows the same basic idea at work:
http://t2.gstatic.com/images?q=tbn:A...Rcnc_P-OYxdAcQ
My less than gracious response to you suggested primary pitch control (and maybe I should have pointed specificallyl to longitudinal control authority) being a more likely source of the problem.
But we don't know. Hopefully, the FDR survived the crash.