Watched it all last night. Too tired to even try to evaluate the timeline business.
However,
It seems to me that the new timeline (WaPo is calling it 815b) may actually be worse for the passengers than the crash was. They may have landed at LAX, but: Kate is on the run, again; she has taken Claire & Aaron hostage and you know that can't end well; Jin is in big trouble with the authorities; Sun is alone; Jack has an imminent funeral and no corpse; Locke is going back to his crap job; and Charlie's arrested for heroin possession. None are good things and most will or should lead to far worse things. Right now, many of the Losties would be better off crashed than at LAX. I wonder if the timeline will be reset again, because 815b is even worse than 815a.