We can tune this by group. For instance no knowledge of PM is required for moderation, but SiteDocClan need to know the site well, likewise it can be difficult for us gods to hand-hold a new pmdevil who is unaware of the basic site concepts so we traditionally set the bar high there too. But this latter point depends on the work the pmdevil is going to do. For some of the tasks we need doing you dont need much Everything knowledge, just the willingness to deal with crufty code, work out what it does, and then refactor it into something simpler and/or more efficient, or just easier to understand.

As an aside i think the thing with new pmdevils is that they think that there is going to be an opportunity to do a lot of cool coding. The truth of course is that even when you are working on such a project most of it is tiny incremental steps to get the overall codebase in the position where the big architectural changes can happen. Releveling for instance involved a whole host of work just to be feasable.