I whole heartedly agree with the author that the biggest advantage of touch devices is the large screen, not a touch interface.
Text input on touch devices is quite variable as I discovered a couple of weeks ago with the Nokia 5800 Firmware V40 update. Prior to this update the registering of taps was a little slow, nothing that I was too concerned with at the time, but it made text input with the T9 alphanumeric keypad a little slower than I�d have liked, not a deal breaker, but not particularly impressive either. After the update the registering of touches is quite a bit faster and I�ve found myself able to type as fast as I did with a physical keypad in the past, to the point that I�m missing a physical keypad less and less. The point here is that how effective you perceive touch to be is quite dependent on how the particular device you are using implements touch and it�s responsiveness.
Touch dose have some advantages depending on what applications you use. I use Ovi maps for navigating quite a lot and there is no way that a dpad or keypad would be as good for navigating as touch. For web browsing I think it�s pretty much down to personal preference, a well designed dpad interface is as quick and user friendly as touch, to me that�s all down to the individual users preference.
What all this sums up is that you have to make the argument that touch is as good as a keypad, not that it�s in any real way better, what it does allow is for a bigger screen, which is a winner every time.