Eh, I think that depends on the office work in question as well as the individual. For example, my typing speed on touchscreen only devices is terrible, even with time spent on the iPhone, n800, N900, etc..Some people have done initial wpm tests and for some I think the time nearly doubles for the same amount of words, though of course the gap will shrink for some with practice. So if your writing a report or a program, I don't see tablets replacing PCs. Of course the iPad does have a keyboard extension..
As for the people in the HF class, I say it varies. But most are beyond technological neophytes. But at the same time, they may not know much about things such as the OS. They aren't computer science programmers or engineers. The class including professor and his collegue consist of one student in the class with a bio-engineer background, my professor and his collegue are applied experimental psychologists, and the rest are AE PhD, general masters students, some aren't interested in Human Factors but are taking the class because it sounded interesting or they work with my professor. While I have a computer science and IT background but no formal undergraduate degree in computer science (my undergrad is in psychology). But not neophytes as some posters here like to imagine.
My nephew is of the same age and my brother keeps telling me how easy he learned to use tools like the VCR, DVD Player, TV and such devices... Aniello