This also speaks to what I'd heard as the likely reason for the gap (with no attribution to Martin, this was someone's interpretation, so thanks Bruce for Martin's take on it). The argument was that Martin is the gardener type, so he has to have his characters react realistically (given their personalities and knowledge) to the situations in which they find themselves. However, Martin did have an idea of where he wanted the story to end up. Problem is, he can't write the story to go in that direction. At least not without massive amounts of adding a situation, seeing how characters would react, cascading the consequences down the line, and seeing if it ends up with the end-state he'd hoped for (and having to scrap massive amounts of work when it doesn't).