This won't be an essay, as I'm short on time, but my personal answer is this:
<PERSON>'s world expanded exponentially with each additional book in the series, and along with all the new information came many new characters, a lot of them to carry exposition and information, yet initially served no real purpose of their own in the sense of the grand epic that was being told. None of the readers was emotionally invested in <PERSON>, for example, but through him we gained a better understanding of the background that shaped his nephew <PERSON>'s character.
This became a problem when the expository characters became secondary characters in their own rights – now each of them had to have his or her own arc, background, characteristics, etc. <PERSON> felt, whether rightly or not, that he couldn't just leave these new characters in the lurch when he executed his originally-planned five-year time skip.
However, what he failed to realize was that there were only so many fictional characters readers could care about. They tended to bond with the ones introduced in the first novel and see those subsequently introduced as no more than tools of exposition, information, or adversity for the primary characters already established. No one cares about <PERSON>'s problems, and I have personally long suspected <PERSON> to be nothing more than a second attempt on <PERSON>'s part to create a more sympathetic and interesting Ser <PERSON>, who's been hanging around for five novels now and has yet to serve any real purpose. 190
In that he only partially succeeded, as <PERSON> serves a classic example of a second-tier character in which no one is really invested, despite <PERSON>'s efforts to the contrary.
This crucial misjudgment on <PERSON>'s part was what led him to scrap the time skip to begin with, and it was an error from which the series has yet to recover, and I seriously doubt it ever will. <PERSON> should have realized his primary characters was where the focus of the story always lay. He should have either abandoned the tertiary ones or relegated their fates briefly after the fact, no matter how unfair to them and their fans it seemed, and stick to his original plan. The fact he didn't do so served to seriously water down the focus and intensity present in the initial first three books as well as eliminate the powerful dramatic effect the skip would have possessed – we would have seen our beloved characters beaten down only to rise again, observe the changes that whould have occured in them for ourselves without having to agonize over every tiny step of their way. Some of the changes the loss of the time skip necessiated - such as suddenly turning <PERSON> from a flawed, conniving, yet ultimately brilliant player into a drunken moron complete with a previously never-heard-of mystical prophecy tailor made to explain her obvious overreaching and mistakes - could have been avoided, and our respect for the character would have remained in tact. 417