I'm planning to upgrade my old Paperwhite just for the hardware update, Processor and battery basically, I feel my current kindle kinda slow, and the battery dies pretty soon if you're with airplane mode off.
I have the wi-fi on permanently and it lasts more than a week of reading books every single day(backlight set to 12). I don't think I would upgrade just to improve that, it's plenty for me.
The hardware upgrade specifically mentioned processor speed. I would be mildly surprised to learn that Kindles are CPU-bound. I have always assumed the device was limited by the screen's refresh rate.
