i can think of plenty of arguments against a touch device:
- a finger is a fat 3 dimensional object, not a stylus, and tends to hit many points on the grid simultaneously, causing unintentional results
- by having to touch a region of the screen, you have to move your finger and consequently your entire hand in the way of the screen, blocking your view of the screen

therefore, mouse & keyboard will always be superior in some way - the cream will rise to the top baby