I would love to create a more AO3-like system like the ones you're suggesting, really, and I plan to look into how the Commons image upload pages are set up—an upload form like that would be far more ideal and user-friendly—but I just don't know if we'd be able to implement that. I'll get back to you on this :)

In any case, if we end up doing it the traditional way, I will certainly edit the image upload page with basic instructions, and probably a fill-in-the-blanks copy of the template so that users don't have to click away from the upload page.