>  ... where small changes for good-intentioned reasoning has led to massive shifts over time that made people wonder why the writers even bothered adapting the story in the first place. 

*cough*  Jason Bourne movies *cough*

I find myself wondering that if the Forsaken and/or their allies got a hold of the horn, the heroes that it summons may be very different from those that appeared for Mat. For example, they may find some of the greatest Darkfriends or Trolloc chieftains from history summoned to their call.

In turn, those Darkfriends (Darkheroes, really) may refuse to follow the commands of the horn bearer until, for example, Ishmael/Moridin raises his own banner.