It sounds like a very reasonable and welcome idea indeed. I'd be willing to support it were it ever to materialize. I'd like to make one suggestion though: from point 2 I get the feeling you were thinking of a framework where needed packages are downloaded on the fly?
I would like to add it might be a good idea to also give the option to use a local source for such packages, so a player can easily update and patch a copy of JJ2 on a computer without an internet connection. Perhaps you had thought of this but it seemed a good idea to also have this written down.