Thanks for your commentary, Blondie.
Thus, it was felt that in the modern-day fulfillment, Jesus was referring to the wicked "generation" of unbelievers who would see both the features that would characterize "the conclusion of the system of things" (syn.te'lei.a) and the system's end (te'los).
I have always loved how the Watch Tower Society switches to the passive voice when discussing the now-rejected teachings of the past -- almost as though some third party were somehow responsible, and the Society were merely an unwitting, innocent bystander. Why can't they write something a bit more direct (and honest): e.g. "We previously taught unequivocally in our exclusive, official capacity as the sole channel between God and men a doctrine which we are now changing and which you are henceforth forbidden to believe. Believe the new teaching! Or else! (Until the next time we change it.)"