I would really like a Voyage upgrade — a bigger screen, adjustable color temperature for night reading, better buttons. (goodereader.com)
The new Nook adds a frontlight with adjustable color temperature like Kobo's ereaders. (blog.the-ebook-reader.com)
In addition to the larger screen the Aura One is also the first ereader to feature a frontlight with adjustable color temperature so that you can filter out blue light if you prefer. (the-ebook-reader.com)