There are only 3 areas that I think dedicated ereaders could improve. One is the option of more fonts - this addresses those with problem eyesight. I can read the Tetrachet (sp?) font on my Nook easier than any other, for instance. The recent introduction of lighting in the unit itself - good start, could improve. Finally, the delicacy of ereaders - it doesn't take much to damage them although some seem to be more resistant to damage than others. I'm not expecting the thing to work if it is thrown to concrete, but my kindle was damaged when I only held it slightly more tightly when I tripped and recovered from a potential fall.
The battery life and the ease of reading is just so far ahead of anything else. I don't WANT it to do anything else. Adding other stuff just adds to the weight and takes away from the primary reason for having the item.