The problem is he's always been a slow writer. He's not going to change at this point. It is what it is. The first three books were excellent and all came out within 2-3 years of each other. I think the Red Wedding, while evilly magnificent, was a mistake that really damaged the narrative. Combine that with no five year gap, as originally planned, and editors who've lost the ability to rein him in, and we get books that are much longer, take forever to arrive and don't impress as much.

All that said, as Martin has said art is not a democracy, so I just use the time waiting on him to finish the story to discover and enjoy many other authors, some of whom can put out a good novel in less than six years. I think Martin has lost interest in the story or more precisely lost interest in editing himself.