Are you only talking about capacitive touch screens? If so, than I agree with you and don't bother reading further. But if you are also talking about resistive touch screens, I couldn't disagree more.

I'm not sure if you were referring to me, but I'm the crazy person who suggested putting a touch pad on the back of a tablet that had a capacitive touch screen. I wouldn't suggest that for a tablet with a resistive touch screen, as I also would never use gnumeric the way you suggest on a tablet with a resistive touch screen. Why would I? I have a stylus and a resistive touch screen. I can pick up the tip and go precisely to a location. Relative cursor movement produced by a mouse or a touch pad is only necessary when your display dimensions are much larger than your tracking area.