I'm very happy with the Paperwhite. There's nothing about the reading experience I'd like them to change. It's just right as it is.
What I would like is an optional mode for automatic wireless. When I set that mode Wifi and 3G will be off but when they're needed they'll come on by themselves and when I'm done with them they'll turn off. I don't want to have to think about this anymore.
I'd also like sync to be automatic, every time I turn the page. I don't want to have to think about that either. I read on my Paperwhite and on a portable phone-like device that lives in my shirt pocket if I'm away from home. I'm 73 and my memory isn't up to par and I often am out and away and go to read and find I haven't synced so I have to search for where I read last. I nearly always do that without much problem but it's a pain and I'd much rather it just did it for me.
However, I think the most important thing they can do is not improve too much. They have it right. The Paperwhite is what an ereader should be just as it is and rather than do those things I just mentioned and keep adding other stuff other people want, I'd like to see them leave it alone. Maybe come out with a new and different model but change the Paperwhite's name to Paperwhite Perennial, or some such. It ain't broke so don't fix it.
Well, there is one thing I really wish they'd do, but only if they can do it without increasing the size or weight or reducing battery life. They can have a pop-out inflatable recliner so I can read comfortably wherever I might be.
Barry