Brandon justified his decisions last year with two things. By focussing the book on Rand and Egwene, he could bring their stories further, and so reach more satisfying climaxes, and he thought it would result in a more faster paced book. The other reason is that they were afraid to postpone the book and disregard their promise to release something last year, and it so happens Brandon wasn't far along enough in Mat/Perrin's storylines in spring 2009 to publish anything where the four storylines would progress simultaneously anyway.

That's not much to do with what I find annoying. What I find annoying is that Brandon decided to throw overboard Jordan's style of chronological storytelling, which had a purpose in a story as complex as his. The structure of TGS is botched, a mess. So much so, that Steven Cooper was never able to come up with a really satisfying chronology... You have Tylee's scene happening twenty days after Malden in the prologue, followed up by a Faile scene happening in the afternoon of Malden, then you have Tuon, soon to be involved in Rand's storyline, with a scene happening just a few days after Tylee's first scene in the prologue, pushed to the middle of the book, when Rand's storyline is way ahead of that. This is just bad writing. Brandon sacrificed coherence to get his fast paced POV switches, disregarded Jordan's style and timeline rules to be able to put a Tuon chapter where he wished etc. After the decision to split the book was made, Brandon had very little time left to re organize the material and fill the gaps, and it shows.

He doesn't have that excuse for TOM. It's OK he returns to Mat and Perrin, but what's not OK with me at all is if he starts returning to Rand/Egwene right at the start of the book, or putting a Graendal scene that ought to have been in TGS in the first place totally out of order, because he finds it convenient. There are limits to how much he can screw with the timelines and retain the WOT style of writing (and story lines coherence), and it seems Brandon is going over this limit. It's a bit frightening, because TGS's timeline, as simple a book as it was, was really hard to follow in places (those who thought it easy usually were completely wrong about the timelines...), and TOM is supposed to be a much more complex book with many more POV characters and story lines. We're gonna loose all our greater perspective if events start happening out of order left and right, and that greater perspective is always something Jordan made sure to keep (it's one thing that made WOT great for theories), leaving many, many time markers everywhere, so we could follow even when story lines got desynchronized (Brandon barely used any in TGS, it's part of the problem that we could rarely tell how Egwene, Tuon and Rand and their timeline related to one another). This might work in another series, but that's not WOT. Not to me, at least. What Brandon did is as if Jordan decided to put Rand's post-Cleansing scene toward the beginning of COT, before the Cleansing happened in the other story lines. Jordan waited until the event common to all story ines had passed in all story lines. As it should be.

Perhaps it will be a lot less messy in TOM itself, but the prologue at least lets fear the worst in this respect.

Brandon could perfectly have split the books as he did and still retain chronological coherence. He screwed it not by not having the four main storylines happen in parallel, he did by not respecting Jordan's style that minor POV characters that crossed with a main storyline ought to appear at the proper place in the chronology, not anywhere in the book. In Jordan's hands, shennanigans like having a Tylee scene set 20 days later than the first Perrin scene, when both characters belong to the same meta-storyline is something that would never happened (and now we see why: Perrin's TGS scenes were "prequels" written by Brandon, and creating contiuity problems like having Perrin still at Malden, when in KOD he was setting to leave right away and it's Tylee who remained behind to deal with the Shaido. Another was the fact Perrin was already aware of the Travelling problem which Brandon had him learn about again in TGS. By all appearances, Jordan planned to have Perrin reappear in the AMOL prologue with the dream scene, which appears to be set weeks later, coinciding with Tuon's return, Tylee's scene and Mat's first appearance.... In short, a structure that made sense, unlike Brandon's).

As for your argument on subtleties, it's really weird. You're saying in essence that Brandon and Harriet agree with the WOT bashers and catered to the wishes of those who stopped really loving Jordan's work after the mid-series over those who kept loving Jordan as much as before and followed him in the late series with enthusiasm. That's.. a weird notion. I'm pretty sure it didn't cross their minds to look at it that way. It may have occured to them that if they split the book more chronologically they would end up with another COT/KOD situation, with a too slow first book and a part 2 with all the good stuff.. but still not enoug resolution as it would be in act three (which of course would have been the case, since then TGS would just have been an act 1, instead of half the act 1 + half the second act) , but I don't think they ever thought "let's dumb it down, because many readers lost patience with the more subtle stuff".