I understand your point.
Try grafx2 port to the caanoo. It is really great, but your stylus can´t reach the absolute corners where you have 6 pixels pallet buttons on the far right.
There are other buttons hard to access because the original app did not count the beveled lost pixels, neither the pixels lost by the format of the stylus against the bevel.
Another example that suffers from the same is the Milkytracker port.
Those 2 are PC apps port running great on the caanoo(320x240), the problems I stated are, somehow, easy to go around if you use them a lot, but they do annoy and take time, not good for a brand new user I guess.
As for touch screen on the DS or whatever use there is, I know nothing.
Only thing I know is that the touch control seems to be an a lot more important input on every nowaday´s gadgets.
Wether we use it or not, it is up to our own needs on our gadgets.
I do use both apps I stated a lot on my handheld, it is important for me and is one of the reasons I got to it in the first place.
Down on the emu side of things, point and click adventures suffers a little too of the same problem, some ´exits´ are simply not reachable that way and I have to do a little push on the joy to help it out. Like I said, problems are easy to go around if you are a persistent user.
I guess gcw zero is made to make general people happy, not only the persistent (crazy) ones
So, if there will ever be a touch screen, I´d hope they keep these things in mind, as they state my solo experiences with it.