For the existing apps that are mouse-centric, I see
touchscreens
replacing them, but for things that are text-centric I don't see that
as a good transition.
TOuchscreens have been tried in the past (the most obviosu example is the
HP150 'Touchscreen PC') and I think they were always found to be less
convenient to use than a mouse or trackball. You have to move your hand
further (keyboard to screen rather than keyboard to mouse on desk near
keybaord), and you arm/hand is not supported (e.g. by resting it on the
desk) when you are doing the pointing.
-tony