Don't worry about having to wait 5 years between books again. There were serious problems getting A Feast For Crows ready. Hell it didn't even exist for a considerable amount of time, A Dance With Dragons was supposed to be the fourth book, skipping a large number of years forward in the story, parts of which would be revealed in flashbacks and characters' thoughts and dreams etc.
That just wasn't working though, so AFFC had to be created, covering that timespan. That in itself created large problems as it meant the book's flow and structure was incredibly complex, covering far more time than any other in the series. The sheer amount of information alone that had to be put in there was a bitch to the publishers, ASOS itself had been hard enough to publish and AFFC was past that amount with hundreds of pages still left to write. The fact that he's splitting the book in two and each version is STILL going to be around the size of AGOT shows just how much work has had to go into this.
Now these scenarios just aren't going to come up with another book in the series. Others might, but if we have to wait more than 3 years between any of the other books, I'd be very surprised. And A Dance With Dragons should come relatively quick as it's half finished already.
I quite like the wait between books myself, though it would indeed be awful if it somehow couldn't be finished. That's my only worry though, I love the anticipation of it and the discussion of what might happen next, not to mention the excitement when the next book is actually out there.
Just one month left!