No keyboard, no mouse, only a multi-touch capable screen and this will somehow liberate software development?
I really don't get it. If it was in addition to the usual input suspects, then sure, that would enable lots of stuff.
But to be able to type, use the mouse for precise on-screen pointing without getting your hand in the way of what you're doing, those are things we already had.
Now you lose those and in return you get interaction with your hands on a relatively small screen.
On screen keyboards are nice, but even a lengthy email would be pretty cumbersome that way.
Choice is good, lack of choice is not 'fascinating', it is limiting. Limitations will drive creative people to come up with ways around those limitations but for now this is what you've got to work with.
Another thing I don't understand from the article is this sentence:
"but the specter of having a small user base for my experiments always discouraged me."
Why does that matter? Not everything is about how many people adopt it. If you can make a small group really happy that counts for something too.