That's a big "Finally" on Krakua. It's also a sign that the Inika/Mahri have completed their mission that Krakua told Vakama about in order for himself to exist.
As for book sales, I agree on the issue being awareness. I mean, every once in a while I see them listed in the Lego Catalog... but I seriously think placing an advertisement within the instruction booklets would up the sales. It works for other sets, it should work for books too.
I'm sure that putting that little "For a further story, read "Bionicle Legends 8"" thing (as in 2005 with the first Hordika Comic and BA 7, or as in 2003 with promoting BC 4) in the comics again would be a good sales move.
Another idea would be promo chapters on bioniclestory.com, something enticing and cliffhanger-filled, making people aware that 1) books exist and 2) you'll find out what happens after the bit you read online... I know that the Prologue and Ch. 1 of Bionicle Legends#7 made me want to rush out and buy it...
Just some suggestions, I'm sure you have your own... but I seriously hope that they realize how much the fans who read the books love the books.
-VK-