One thing I can imagine is questions about how to modularise specific programs as much as possible. Something that is necessary in open source more than anywhere else.
Building on the example of modularity as a reference for the larger discussion of the direction of the site, I would hope to see discussions around community practices (e.g. in managing modules), rather than technical discussions. As overactor says, there are already resources out there for technical discussions (like programming and I would add modular development), but a very few on how to manage a project which employs modular development.
I like the proposal's theme:
questions regarding motivation, marketing, organisation and coding pertaining specifically to open source projects.
...but I would limit the "coding" to none technical discussions (point to existing work) and rather focus on coding issues like, "how to learn to program through open source projects," "creating/enforcing coding standards/styles" "managing diverse/multiple programming languages in a project" "auditing code submissions (security)" etc.