The problem with all of the above is you are talking about a PS user that has had 'training' via classes, etc. I was under the impression we were talking about a user that had never seen either Linux (or PS for the sake of this discussion) and had to accomplish a task and they were going to use installed documentation. That was the gist of this thread, or so I perceived, apologies if my perception is misguided. Given that scenario and your discussion of Photoshop's manual and notwithstanding the enormous changes in the application since say PS 7 to todays CS versions (which you seem to discount above) the situation is the same. The manual for PS assumes some knowledge of the app based on terminology, etc. Yes, there is a glossary but Linux man pages also point to 'See Also' man pages. Not all that different of a scenario.
If you are in unfamiliar territory and need to know how to do something specific, the PS manual is just as lacking as the Linux man pages and rightfully so, no author can account for all the scenarios a user might run into and some basic needs MIGHT be adressed, I have found the same to be true of many (not all) man pages as well.
What does burn mean? What is the purpose of the Clone tool? How do I use the magic wand or masking or layers? If you think the PS manual is going to help the green user with the above without them having to google a bit I would say you are projecting your own knowledge of the app to a user that knows nothing.