That would suck on a level I can't even begin to contemplate, I've spent a lot of money on that series, the Idea that It may end up on a shelf with just the last beeok left to write doesn't sit very well with me.
As of last week, it is due "no later than November 2012", and probably not earlier than July 2012. The March 2012 date is looking unrealistic. http://www.dragonmount.com/index.php/News/amol/a-memory-of-light-release-date-speculation-r202
Well it does take time to write great gbooks and probably to write a FINAL BOOK to tie up all the loose ends - have not read them all yet, but am rereading and looking forward to the final one! So if the last two were that good, I would think it would be waiting for a few months longer than them just rushing it to the publishers to get it out quick, just to make you "happy1". And if it sucked it would not make you happy - so patience for a great ending I think after all this time - what is a few mor months or a so to wait?
I read on Sanderson's website that the book is written but the release date is slated for early January. This is because Jordans wife is the editor and wants to make sure they get this as right as possible, being the last book. Apparently she also ran herself ragged trying to get the last one done quickly so they want to give her enough time without sacrificing her health or quality. He went on to say that the date COULD change by a week or so depending on developments.
Here in The Netherlands it's still waiting for the Dutch version and had already been delayed twice. Should have been in store May 22nd. ;-( and that was already 2 days too late (it would have made a great gift for my husband)