I'm not sure how useful that could be. Unless you have some standardized method of getting such information from a script (a master module, or something, to which the other modules interface, and only addons that conform to said standard at that), pretty much all you can get is alias names and events, leaving you in the dark as to what it actually does. I don't see how that will increase the modularity of a script.
On the other hand, perhaps you had something in mind that I haven't thought of. I'd be interested to hear what you were thinking of doing, specifically.
On the third hand, I am not sure I'd like some scripts to know when I load/unload another. I imagine it could be abused somehow. If this were added, the prompting that is done with the current implementation of on load should apply to the extension as well.
As an aside, I personally like the idea of having some sort of main module that makes modules work together, but I think the addons should be responsible for communicating with it via their own on load/unload, which could prevent, or at least reduce, compatibility issues with addons from some other source (if they don't follow the standard, they don't tell the main script anything at all, but at least they aren't giving it invalid/useless information).
Just my take on it all.
