Hi Karl, sorry, not been paying attention over the last few days....
"...your concerns that we easily could be monstered by this project." What you are trying to do is very leading edge, and seems like it could be mired in bureaucracy easily. People do not really like cutting edge, they prefer someone else take the risks and they can swamp such projects with layers of bureaucratic meddling. Another part of it can be that you, your team of developers, get so enarmoured of what they are doing they forget that they are on a journey that has to encourage others to follow. Things can become big, adding this functionality to enhance that ability which resulted from this idea, which grew out of that need.
After all that, this functionality can do great things, but is so esoteric that comparatively few, if any, users actually use that functionality, mainly because they really don't need it. I suspect that Microsoft Office is pretty much like that, so much is included in the core package that it takes up so much HD space that it is little more than bloatware. Great functionality, but who actually uses it? Would it not be better as addins, or plugins? Been there, done that and the project was cut because it wasn't producing anything useful. An e-commerce project in Oz did this so badly that it nearly broke the company that was doing it.
The last part of this is that wanting to get such a package right becomes such a priority that it gets so big, that people spend so much time on things like bug fixes and optimizing that they don't do any development work. Usually what happens is someone else develops a similar tool that is better, smaller, faster and more effective. Not been involved in such an outcome, but I have heard of them.
Right now, Moodle is the best tool of its type, a Learning Management System. More than a few years ago, it was Blackboard, and before that something else, like WebCT. Moodle is, right now, the trailblazer, on the leading edge of development and implementation. I suspect that projects like yours, mat take Moodle into different directions which may mean Moodle remains on the leading edge, or may threaten Moodle by pulling its core in so many different directions that it too loses its way. Who knows? As well, who knows what developments may occur?
Hardware changes, which influences software changes, which influences hardware and so on, an eternal cycle. Who knew what HTML5 could do when first touted? Who knows what it may achieve? What will replace that? PHP is somewhat limited, so may be replaced by something very different, and if Moodle doesn't make the change, how long will it survive?
In short, we don't have crystal balls to gaze into, tea leaves just don't cut it, and economic forecasts are just as flawed, perhaps even more so. We don't know what will happen so just better to be prepared to meet any eventuality, I suggest. Keep the project as flexible as you can to change to meet different criteria. As to how you can do that, sorry, no idea!... But.. Good Luck!!!