Judging from the more popular problems I would think some of the basics for things like Glow Plug function and removal, maybe check of actual tip destruction. 2. The bottle feed method, how do we get down to just a known source of air into an IP by removing the filter and the return line into what? not a five gallon bucket. 3. Changing the timing, seems most new members do not know what to do with the process of twisting the pump. They likely are not looking at the online stuff that is on here. And given another place here to look called a How To, we might just solve their problems.
That is my stab at it for now. But thinking we cover some of the minor problems not engine rebuilds.
My 2 pennies worth.