FG,
since I haven`t seen the material, I usually should not comment. However, you mentioned a couple of topics that "may not be important" to OPS people and I must say that I disagree.
R/T phraseology is quite important. If you ever had the pleasure to do flight following via HF you will soon find out that you won`t get very far with the usual colloquial talk common on company frequencies. Personally, I also find it quite helpful, when dealing with ATC in Asia, since the English of some controllers tends to be a little limited. I agree that it may appear a little out of place for the usual LGW-EDI run.
As far as rules of the air and "in depth" maintenance theory is concerned. You may also say that as a car dealer you don`t need a drivers license nor knowledge about the inside of a car (yet most dealers I know tend to have this knoweldge - and usually with reason). The systems are important, so that you can find your way across the MEL a little easier and also to judge as of how serious a mx defect may be that is reported to you.
Since you mentioned the FAA Dispatcher License. The study of the theory for this course is done from the same book as the ATPL as well.
Cheers
fcit